I know it's common here to assume that different coloured movement parts indicate some sort of nefarious modification, but one of the features that was touted by Omega for these movements at the time was that the entire automatic module could be swapped as a unit for maintenance purposes. This started with the 470 series movements, and before that it required disassembly of the automatic winding system to replace any part in that system - the new "modular" approach was seen to be an advance in servicing options. Of course these modules have not been offered for a long time.
The fact is the plating that Omega used varied quite a lot over the years in the colour tone they used, so if a replacement module was installed, it could be a very different shade like the example above. In addition to the fact that plating can sometimes not adhere well and will flake off some parts and not others during service (I have even had sections of one plate flake off and the others areas of the same part were fine) can lead to a movement that looks very odd, but has not been "tampered with" in any way.
If you value a movement that all looks the same that's fine and your choice, but for some movements it just shows that it's had a normal life, just like patina on the exterior does.
Cheers, Al
Click to expand...