I did read that a case back with ref. 136.011 is indeed from a Seamaster and not a Genève. Forgot to mention it in my original post.
I wouldn't consider that to be a dealbreaker myself though.
I did find this after looking into it more now:
https://www.poshtime.com/500.039/Omega-Geneve-Seamaster-136.011-c.1967.php
Would a Genève Seamaster be possible when they were transitioning?
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