Info on my 2638-4?

It’s from no later than 1947 and I agree has had a service dial fitted at some point.

I think it is slightly later, 1948 to 1950. Cal. 30,10 had exposed springs and was used in the Ref. 2500 Centenary, which was produced beginning in 1948 (with an upgraded movement).

I have seen several examples of these dials on late 1940’s watches, so I believe it to be correct for this watch. It could be a “prototype” as intimated by Omega. My German isn’t very good, but that’s what they seem to be saying in that letter.

The movement looks like it was either put together with various parts at the factory (makes sense for a “prototype”) or had significant damage and was rebuilt with replacement parts, including the balance assembly. I don’t think that we will ever know what happened there.

There are too many unknowns here to really be able to determine how this example came to be.
gatorcpa