Need Help for OMEGA ARMY ? MILITARY ? or please advise

I find this sunday on a garage sale I am not sure but can be military ,army ? the OMEGA dial is not redonne and is marked OMEGA and logo the movement is OMEGA nothing marked,no words,no number but is OMEGA from the 1915 to 1920,That I am sure because I have the same movement in a trench OMEGA wristwatch.And the case nothing marked, but looks like is made in the 30s with soldered lugs like most of the military watch.
So please I need yours advise.And need your expertise about this really interested OMEGA.I am more specialized with LONGINES OMEGA I have just fews ,with MILITARY FAT 53 and 6B/159,.
So please help me on this one.
THANK YOU

OTHERS PICS

And probably not even be an Omega movement.