Help authenticating Hamilton Military Watches

I have been looking for a military watch, Omega’s are a little above what I want to spend on this particular style watch,

I came across these Hamilton’s but have some questions in regards to dial, movement etc

#1 Hamilton GS Tropicalized
1. Movement, in the brief amount of research I have completed, the movement on other examples states S75S. On this example it is not visible. However I have seen movements like this in other GS examples.

2. Case, looks a little too clean. Case back states 678 while outside case states 684.

Any info on this particular model would be helpful.

Upon further research, it appears there are many cases identical to this one that are in fact fakes.

Hopefully this will help prevent other members from making a costly mistake.

It's a fake, well documented on MWR forum

If youre looking to get into military watches at a reasonable price you should have a look at Bulova A11 aswell.
Heres mine with a coin edge bezel:

That’s very nice, the coin edge looks great.

Can anyone weight in on this watch below