How to Identify a Vintage Omega – Part 1

 In Collecting Watches

Omega is a great brand. It doesn’t matter if you prefer new or vintage. It just is.

However, if you buy a new one from an AD or boutique, the risk of buying a lemon is very low. Yes, you can buy one with a factory flaw, but that’s out of your hands. With vintage Omegas, it’s anything but easy.

Nevertheless, I’d like to provide some guidelines. Of course, you’ll have to do an awful lot of research on your own.

In this part of the identification guide for vintage Omega watches, we’ll focus on the movements.

Identifying the movement

Please don’t buy a vintage watch, let alone an Omega, without having a look at the movement. If you ask the seller for pictures of the movement, and you get a response like “I can’t” or “I don’t have the tools” or just a plain “no”, it’s best to just skip that one.

Omega movements, from the 1930s and 1940s, usually have the calibre number under the balance. From the late 1940s on, the number was located on one of the bridges, usually the same one as the serial number.

Serial numbers

Every Omega movement has a serial number. In pocket watches from the early 1900s, you can find it on the dial side of the baseplate. In other words, you have to disassemble the watch to access it. Later on, the serial was always on one of the bridges.

You can find a list of serial numbers for Omega at Chronomaddox, a useful Omega resource created by the late Chuck Maddox. Note that this list doesn’t apply to Speedmasters. Speedies have a separate list, compiled by Roman Hartmann and you can check it here.

30mm movements

The 30T2 and its derivatives are a legend in their own right. They can be tricky, though.

30T2 and derivatives

Note that various versions of the calibre 30T2 sometimes have a signature of the base calibre, while that’s not necessarily the full calibre number. For example, the 30T2 PC and 30T2 PC AM are both signed 30T2 PC, because the only difference is an anti-magnetic balance in the AM version.

How to identify a vintage Omega

Calibre 30T2 PC AM from a ref. MI 2214/9. The serial number dates it to 1946 or thereabouts. Note the absence of “AM” in the markings under the balance.

The Ranfft movement archive entries for movements of various Omega families list differences between particular movements of a calibre family. It’s always good to check that out when looking at a movement.

For example, when you see a cal. 265 with a flat hairspring, while it’s supposed to have a Breguet overcoil, you can be sure that it’s actually a 269 movement with the wrong balance.


The 30T2 had a few chronometer versions, all of a higher grade than the non-chronometer versions. These have the suffix RG in the number. You can easily recognize the RG by its distinctive regulator.

I’ve encountered cases, where a dial signed “Chronometre Omega” was fitted to a non-RG 30mm movement. This is – and will always be – wrong. A non-RG 30mm movement + a “chronometre” dial = frankenwatch. No exceptions.

60X series

This is nothing more than a 5XX base without the automatic winding assembly. Of course, the barrel is different as well. They were mostly used in the Geneve collection, however, a few Seamaster De Ville models had it as well.

Theoretically, it fits in a case intended for a 5XX. If you see a 60X series movement in a case with a reference that tells you it’s a model which is supposed to be equipped with a 5XX-series automatic, that’s obviously wrong.


Until the 1990s, the only supplier of chronograph movements for Omega was Lemania. One of the best-known ones is the cal. CH27 C12, later known as the cal. 321. There are, however, differences between the CH27 C12 and the 321.

The 321 is always marked as such and always has copper-colored plating. So, if you’re checking out an Omega chronograph from the 1950s, which is supposed to have a cal. 321 but it has a silvery finish on the plates, cocks, and bridges, and it doesn’t have the 321 marking, it’s simply not a 321.

Rotor automatics and their issues

Omega’s rotor automatics of the 5XX family (and everything that followed) are great. Still, they have a few issues worth noting.

You need to be extremely careful with signs of issues with the rotor. The one thing that’s known to go wrong with these movements is the axle of the rotor. When it wears out, the rotor will start rubbing against the bridge on which it sits (upper bridge for automatic device), and against the case back. The edge on the rotor will have an obvious loss of plating. So will the upper bridge, most likely. The inner side of the case back will have a characteristic circular trace on it.

When you see that, best skip that one. It may be, that the issue has been repaired. But can you be sure? Nope.

It’s also not uncommon to see movements built from spare parts. You can often spot them by an inconsistent tone of the plating throughout the various components. Of course, some parts will change color due to the different solutions they were cleaned in during a service. However, if one part has an almost yellow gold color, and the other one has a deep, dark copper tone, you can be sure they didn’t leave the factory together.

Another example of frankenising is using parts from Tissot counterparts in movements, which the two brands shared. Notably, that’s the case with the Omega 1480 and the Tissot 2471. Well, technically they’re the same thing. So, the parts are interchangeable.

I’ve seen rotors from the Tissot transplanted in an Omega. If you see something like that. You guessed it. Walk away.

All in all

Omega is a well-documented brand. As long as you follow the basic rules of identifying the movement, and you keep the possible issues that are mentioned above in mind, you’re in the clear.

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Showing 10 comments
  • Avatar
    Richard Janes Cullis

    Love the site. I am looking at an “Omega” pocket watch with serial number 1350547. It would seem this should be from 1895 to 1902. The serial number is beside the winding wheel on the motor barrel bridge. My issue is that I can see the number just by opening the case whereas your site says I need to dissassemble the watch to see the number. Also only the only jewel evident is the balance end stone (I only have a photo of the movement). Does this sound like it could be genuine?

  • Avatar

    The mechanism is 6727172 ,how can I get more details about this a wristwatch of ladies.please

  • Avatar
    Paul C

    Hi I just purchased an Omega pocket watch with the serial number 11172450 and wondering the age please

    • Melvin Hollenberg
      Melvin Hollenberg

      Hi Paul,

      The serial number points to 1947 or 1948.

    • Avatar
      Sameer Kulkarni

      I got a pocket watch with all no 10078392. What might be the manufacturing year

  • Avatar
    Chayal M L

    Great article.


    • Michał Kolwas
      Michał Kolwas

      Glad you like it!

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