what do you guys think of this caseback? it was on a straight lug seamaster 300 with a 18 serial

 

Curious to hear the experts weigh in. I have some knowledge of Rolex patents (mainly the screw down crown) so interested to learn more about Omega.

 

Seems like the same as on this one https://omegaforums.net/threads/sm300-ref-14755-1-with-extract-from-omega.3879/