It looks like it could be a 2791 to me, which is a 1950's reference which has a very nice and quite substantial case size, I think around 36mm. The hand winding movement will be from the 30mm family of movements and a 266 or 267. I sourced a 2791 with a black gloss dial for my brother-in-law a few years ago and I must say I'm slightly envious whenever I see him wearing it!
https://www.omegawatches.com/watch-omega-seamaster-omega-ko-2791Click to expand...