Need help identify this C-Case Seamaster

Hello everyone,
I recently came across this Seamaster for sale on Facebook. Solid 14K case. Does anyone have any info on this piece? I’ve never seen a Seamaster C-Case like this before, and also that case back logo too. Frankenstein?

Not merely Franken - a frankenfaken of special note. The head of fakes went out for a long lunch and told the intern to do the writing on the dial, who, after after several minutes of studied concentration to complete his work, then popped some nitrous oxide before turning his attention to the caseback.

What even is that case back?

I happen to have a very similar 14k gold Omega Seamaster. But mine is a 1966 movement, D&A case, gold tone dial, and a smooth caseback. What I find most interesting is that yours also has some texturing on the gold instead of polish. I thought that might have been added to mine to cover up scratches, but I liked the look and decided to keep it unpolished. Now I'm wondering if that was a finish option back then?

Yeah, the "Seamaster" mark on the dial looks smugged. Mine is a lot more crisp. It is possible the dial was re-touched. Mine has some damage on it and I elected not to have it retouched.

Not convenient to open my caseback, but mine is different anyway (smooth with no Neptune Chariot). My understanding is that in this period the tax on importing gold cases was very high so Omega would ship movements to the US to be installed in cases manufactured domestically.

Also looking at this forum, it looks like another D&A case has a similar funky Omega symbol inside the case, so I wouldn't be surprised if mine looks similar?

https://omegaforums.net/threads/need-help-with-omega-p-6638-model.91892/