https://www.google.com/search?site=...edr...0...1ac.1.64.img..7.19.3066.UY_WUEGlkhc Lots and lots. Be aware that some shown in the above link are gold filled or gold capped but there are still plenty of solid gold Seamaster models to chose from.
Aaaahhhh, n00bs! There were probably a couple hundred different case references during the 1950's - it's not like there were 5 or 6. I don't think anybody here could list them all definitively.
Many thanks to everyone i really appreciate your answers. Just a small addition, what about gold bracelets? Particularly 'chunky', if i can use this word for a masterpiece, size?
You're going to have to wait for the true '50s Omega experts to come along to answer questions about bracelets. My understanding is that Omega offered bracelets in the 1950s but the bracelets were more often an accessory item, the watches generally being supplied with leather straps. I'm surmising that any factory original bracelet supplied on an Omega watch would have been more likely to equip a Constellation then a Seamaster. Now watch. A host of members will now come on here and add beautiful photos of 1950s vintage gold Seamasters wearing factory original gold bracelets.