Help identifying the reference + year of this vintage Omega

Posts
1
Likes
0
Hi, I’m trying to identify this vintage Omega that belonged to my father.
It’s manual wind, no date, stainless steel, with a silver dial, applied gold markers and only the applied Omega logo - no text on the dial.
My father was born in 1947, and I believe he may have received the watch for his confirmation around 1961. It says Seamaster on the back.
Any help identifying the reference, caliber and approximate year would be greatly appreciated.
Thanks!