Looks original to me. Golden Mercury was a genuine Omega line, sold mainly through the Italian market in the 1960s, typically on cal. 552/565 automatics. The print quality on yours is consistent with an original - crisp lettering, SWISS MADE sitting correctly at the dial edge below the minute track, and an even minute track with no smudging around the applied markers. Redials usually show fat or uneven printing and misplaced SWISS MADE text, and I don’t see either here.
If you want to pin it down, post the reference number from inside the case back and a photo of the movement - happy to take a look. I run watchbreaker.com, where I identify vintage Omega watches and movements from photos.