Any guesses as to the origins of this lovely watch?

I recently got this lovely old watch. From measurements/design etc. I think it is an Omega from 1930s/40s
It is sterile. Would this be a military thing?
Is the dual tone gold?
The width is 28mm and the length is 34mm.
Can anyone add any facts/theories?
Here are a few photos.
Thank you!
The bracelet is a Clewco