Help with Identifying Omega Trench Watch

Hey everyone,

I've gotten myself into quite the predicament with an old Omega trench watch I was keen on restoring. My watchmaker has hit a wall because we are at a loss for finding a balance staff. Without a caliber number or part numbers, I fear we might not be able to source the exact part we need. I have attached photos of the watch itself, case, and some photos of the movement disassembled. It's a long shot but I figured if there was any place on the internet that might be able to provide additional information, it would be here.

We believe the movement is an old Omega 12 lignes, however we don't have much more info than that. No discernable markings anywhere else on the plates, except serial number of course. Any help at all would be appreciated and of course thank you all for your time

Thanks,

Julian

An additional question I forgot to include in my original post:

Would a balance for the same size movement be different for a pocket watch and wrist watch from the same era? Because I found this pocket watch which seemed to have an identical movement but different stem position obviously.

https://www.ebay.ca/itm/Omega-siver...rentrq:b86df2791780a4d729c5b455fff4e528|iid:1

Bump, watchmaker and myself still haven't found anything suitable for parts information.

This may sound like a stupid question. Would it be at all possible for the balances to be interchangeable between a pocket watch 12''' with the stem at 12 versus the stem at 3 on the wristwatch version? It is much easier for me to pay donor 12''' movements than wristwatch ones.

It's rare for me to see someone selling a balance alone so I'll have to take a shot on a whole working movement. Not my cheapest gamble but as you said, it would have been easier for Omega to produce 1 balance at the time. Thanks as usual Archer!

For example, I found this reasonably priced movement that looks to be correct. Just wasn't 100% sure about the balances. Might give it a shot now.

https://www.ebay.ca/itm/164787781539

Thank @Archer! I think I may have found a site that supplies the correct balance staff. The key to getting them to pop up was including LB or SB in my serach.

https://urdelar.se/products/omega-12-lb-sb-balance-staff-dcn-517