A slightly odd first post, but I'm new to Omega, so please humour me

I've been looking at 2264.50 watches, most seem to have a fairly small hippocampus on the case back, but I've come across a couple that have something much bigger, which I have to admit to rather liking (see pic).

Is this 'hippocampus size' on 2264.50 a year of manufacture variance? A sign of replacement on servicing? Other?

Thanks

 

Well that's not the right caseback. It looks like the one from the later generation of Coaxial Seamasters. Not sure if they're compatible

This one is from a 2531.80, which would be the same caseback as on a 2264.50


This one is from a coaxial 2220.80, which looks similar to yours

 

Blimey; Thanks!

 

Yes that's definitely not right...

 

The seller of the one I pictured earlier is telling me that there was a crossover period where some older watches had new style backs fitted, and vice versa.
Thank you for the advice thus far, it's certainly alarmed me.
I've dropped Omega a line asking whether such crossovers took place.

 

Highly skeptical of that. I've handled thousands of SMPs but never one with a switched caseback. But who knows?

 

Thank you for the advice from the 2 of you and, Al, by PM.
I thought I'd just give a quick update now that the matter appears to be resolved (I didn't mention in this thread, because I was feeling a little bruised, but I'd already ordered the watch in question when I posted the original question!).
You were both spot on, here's the definitive answer 'from the horses mouth':

 

As a 'PS', yesterday, I took delivery of a 2231.50 - first impressions are really, really good (unlike my 16710, I could actually see the hands when I woke at 4 this morning! - one of the reasons the 16710 is getting the boot). On the downside, all the inner edges of the bracelet links seem very sharp - it's been Omega-serviced, I imagine the sharp edges are the result of polishing; I think I'll have to ask for them to do a 'blunting' of all the link edges.