So I have this vintage 420 cal (possibly a Seamaster?) and it’s in a star watch co 10k Gold filled case. I want to replace the caseback on it but can’t find any details confirming the specs of what I should look for.
I think it’d be cool to have a Seamaster case back with the logo. Any ideas as to what the case back for a vintage 420 caliber Seamaster should be?

 

It would probably be easier to just buy a Seamaster.

 

I have an Omega Seamaster with 420 movement which belonged to my grandfather. As you can see from the polished back it has no Seamaster logo. The pics of case back and movement were prior to a service and replacement of the non-Omega crown. The only thing it used to state on the case back is "waterproof".