Help! Authenticity/ general advice would be greatly appreciated

hi everyone, new to the forum here.

I live in India, where it's quite difficult to find genuine/ non franky vintage watches. I was looking at acquiring this omega porcelain recently off eBay, but have my doubts and as you guys are the experts, was looking for some opinions on it. By talking to some very helpful people I gathered that it looks like an open faced pocket watch that was converted into a wrist watch. It looks as though all the parts are original except for the lugs and maybe the crown. Unfortunately as with many listings in this country, the pictures aren't perfect, but I will try to acquire some more and post them here as I get them.
Again, thanks for the help!

It looks like a pocket watch. The position of the crown, the hinged back, enamel dial...What's the size?. If it is big (40+ mm) it is a pocket watch.

Definitly a pocketwatch converted to a wristwatch. I would not buy that.