What Reference is This Omega? Recent Purchase--Needs Service.

I bought this white gold Omega recently and I'm waiting for it to arrive. I paid $800 for it. I doubt that is an excellent price based on some of the nicer condition watches I saw on eBay, but I really like the look of the white gold without plating (I'm guessing the rhodium plating wore off in places and it probably got polished to give it an even finish?). Let me know if you think it looks incorrect for any reason. I'm fairly new to vintage watches, and this is my first omega. Figure it's best to learn from my mistakes if I got burned.

As for reference, best I can tell, it looks like an ST 166.0204 from 1978 (but that is stainless steel). Did Omega happen to make that reference in white gold? I'll know more when I can get the case back off but I appreciate any insight.

Unfortunately, I don't have a picture of the full caseback. I'll upload one once it arrives. As for the gold, white gold has a bit of a yellow tent when it isn't plated. I asked the seller, and they confirmed it was white gold, but can get a yellowish tent depending on the lighting. I think this picture against a black background does a better job of showing the white gold (yellow gold would definitely look yellow in this pic). look yellow against this black background).

Admittedly, I am kinda out on a limb buying a watch without a picture of the full case back or internal movement... But it was donated so worse case my overpayment is going to the org's non-profit purpose....

Not a great picture, but I did get the case back off at a watch repair shop. Looks like it needs a new crown, and new glass, and possibly more (quick change date isn't working). Looking at $800 to repair it (early estimate from might go up?). And they offer polishing if I want. They don't think it is the original finish (as I suspected). But I'm still inclined to keep the scratches since I think it adds character. What are people's thoughts on polishing a case that probably isn't the original finish (they said it was unusual)? It also sounds like there are a few scratches on the movement from a screw that came loose at some point in its history.

Anyway, assuming they can repair it for $800, I'll be in for $1600 on the watch (plus tax/shipping). Any opinions on whether to polish, the cost of servicing it, and generally whether I got burned on my first omega buy?