Can Omega restore this PO to like-new condition?

502 to right

I've had multiple Seamasters serviced by Omega in the last 5 years so I have a decent idea of what to expect.

With a full service you will have included in the standard price new hands, new crowns, new gaskets, a serviced movement (and any internal movement parts that are worn will be replaced), and a refinished case and bracelet. The case refinishing should return it to near new condition. If there are any deep dings those won't be taken out. But I don't see any deep dings in the photos. There are some deeper scratches on the clasp that likely won't be entirely taken out. They can't get too aggressive there or they will shallow out the Omega engravings. I've noticed they don't get too aggressive on the caseback either so there might be a few nicks visible when they're done. Again, I think it's because they don't want to distort any engravings. If you aren't expecting a 100% new looking watch I think you will be pleased. It will look super "eye clean" on the wrist.

With respect to the bezel you have two choices, live with it as is or pay for a replacement. If a replacement, they don't replace just the bezel insert (like Rolex), they replace the entire bezel assembly. In the USA the aluminum bezel/bezel assembly will run about $330. It's not cheap but it will obviously look new (because it is new). I've always had my bezels replaced as I think it's worth the money (even though it's expensive). The good thing is that they return the old bezel so you could sell it or at least have it if anything went catastrophically wrong in the future.

So if the purchase price + service + bezel is a price you're comfortable with then go for it. It's a fantastic watch and I own one. I much prefer the first gen to the ceramic variants.

My last thought: I'm 99% certain Omega never replaced with the 2500C movement with a 2500D movement during service. There are parts they would have replaced in the 2500C during service but it would not turn into a 2500D.