1960s Seamaster 30 Help

My grandfather bought this Seamaster in the 60s and I inherited it from my father last year. I've been trying to figure out more information about it and would appreciate any help from anyone who may know about these.

Based on the movement and case it appears to be a Seamaster 30 however I don't know exactly what year. I also am curious why there is no '30' on the dial. It seems like every Seamaster 30 I see online includes the number.

Omega sent this watch to Switzerland last year to be serviced (I still have any original parts that were replaced during the service). Omega offered to dig up the history/certificate of the watch for a small fee. When they returned the watch Omega said that some years of their records were destroyed in a fire and this watch fell within those years so it wasn't possible.

Any input is appreciated!

Thanks for the information - very much appreciated! This is the dial that has been on the watch for 30+ years since my father inherited it. So if the dial was replaced it was long ago. Yes the crown, hands, and hesalite were replaced, but I have the originals.