Thanks very much for the information
@ApolloXVII and
@hoipolloi
I was starting to suspect a refinish after inspecting the pictures again. Out of curiosity, what do you think would be a good price on a ref.125.005? They don't seem to come up very often and I haven't been able to find much about them or the 651 caliber. I have seen a few in gold (plated?) cases, as well as two tone and plain steel cases. I think i prefer the plain steel myself.
It's a slim elegant and understated dress watch. I agree the steel suits it best. Gold looks wrong on this, and two-tone never looks right to me on any watch. (Ymmv). White gold/platinum is fine though if you wanna be extravagant ;o)
Mine has an issue. My now retired watchmaker told me it needs a new balance as the hairspring is a bit screwed up, but I might try to find someone skilled enough to sort it out without replacing it.
The 651 is actually a peseaux/eta 7001 movement which is still used by a number of other manufacturers for small seconds watches. I don't know to what extent - if at all - Omega muck around with it. When the problem with mine was diagnosed I asked on here if the peseaux 7001 balance (I can find those) is a direct replacement, but no-one knew.
I have one in a Nomos Club (lovely watch by the way). On a timing machine that has a delta at full wind of 8 seconds over all 6 positions, and it runs on the wrist about +2.5 per day. Small seconds so not easy to be precise.
Also have one in a Junghans Meister - another great performer - delta of 6 at full wind, and about +2 on the wrist.
I suspect that both Nomos and Junghans do extra adjustments to get that level of performance, unless I'm just lucky..
Both of those hack, so easy to correct, but from memory I don't think the Omega 651 version does.
Can't help you on the price as like you say not many come up, but lovely watch if you want something in that sort of style.