Dear OF - stumpled on this Seamaster when browsing through an auction for another Omega - and im a little pussled - or maybe just dont have enough knowledge on vintage Omega's.
I was under the impression that the seamaster always came in a sealed case? So the ref. number would be 1-X-(5,6,7,8).(x)xxx - or.... did the seamaster come in non-watertight versions as well??

 

The simple explanation is that it has been redialled and is not in fact a Seamaster of any kind. Look at the font of automatic. You see that on a particular Connie version only. If you search on the case number, you will see it is actually a Geneve dress watch.

https://www.omegawatches.com/watch-omega-geneve-omega-ba-162-0033

 

That was my conclusion as well, just not 100% sure - concerning though that the auction curator haven't caught it and values it in the 2500 € range