It's beautiful!

I can't help with ID on the maker.
If it were mine, I'd light up the bore and see how it looks.
I'd have the metal out of the wood and get the lock and triggers out and service them. I'd take a very close look at the wood - especially through the head and wrist for cracks and repairs.
My far-flung guess is that it's close to running shape - and I'd run it!