Help with Seamaster Cosmic Case

Hi,
I was hoping someone who is more knowledgeable than me could help.
I bought a Seamaster Cosmic quite awhile back in pieces with no case. I had a watchmaker put it together for me and lucked out that I actually had all the parts. The problem is I bought a case that was the wrong case ref., so it doesn't fit. Doh!
I'm hoping someone might know which case ref. I should be getting. Based on serial # year placement, I think it is this one. 166.049 - https://www.omegawatches.com/planet-omega/heritage/vintage-details/25229/ All the other Case ref's are 1967 and I think my serial number is too high to be one of those.
I just don't want to make the same mistake twice. Expert advice please and thank you.
Watch info, Serial: 27618911, 24 jewel, 752 movement.

Thanks for the response Archer. I bought one on eBay and like an idiot didn't research, it's a 135.016, which I can see now is for a '66 with 601 movement. When I got it, it seemed like the dial screwed in and fit perfect. However once he had all the parts together he couldn't get it to fit into the case of course.

Hello Kevin,

There are two possible case that would fit your cal. 752.

The first, and the one I prefer is the 166.036. It look like this :




Or you could go for the reference 166.035, king of helmet case :

You may grab this 166036 case on eBay : 132379651226
Good luck.

The only concern I have is I'd like to try to be correct and use parts that would have come with mine originally. Those two are specifically 1967. i think with my serial # I'm a little later than that which would be the .049
I suppose they all fit the 752 and were for a Cosmic, so it would get me together and wearable.
Thanks for the pics and advice.

Yes, indeed you have gold index on your dial. Didn't notice. So case 166.049 would be the right thing.