Is this Omega Seamaster Cosmic ref 166.128 Authentic and is it worth buying for $800?

I recently sold one just like this, but with an aftermarket (Uncle Seiko) 1171 bracelet. Some sale photos below.
The main difference is the hands - the ones on mine were white and I wonder if the ones on yours may have been replaced at some point? and The hippocampus on the case back is perhaps also a bit off in comparison, but the pictures are not that clear (unfortunately I don't have more case back photos either).
I'd also check the end links - they should be stamped 676 if they are Omega. As a price guide, mine sold for GBP£750 on C24, so a similar price.

It'll be a cal 1012, but you're unlikely to get a movement picture as these cases are notoriously hard to open.

These aren’t that hard to find and I do think the bracelet is quite worth $400 as it’s a later 1171 with what appears to be aftermarket Endlinks.
I’ve also got concerns about the caseback.
Personally I’d keep looking, $800 should get you an original cosmic 2000 with original bracelet and Endlinks