Very, VERY cool piece. I love the hasty rough nature of the stock shaping, complete with clear tool evidence and 'faceting.'
My speculation would be that pieces like this - especially pieces without evidence of a guard ever being installed - were probably estate pieces following a gunstocker's death. And there are other floating around, not all of which look like this architecture, so it makes some sense to me anyway. There are numerous probate inventories indicating that some of these guys were clearly still working up until the point they croaked, and once everything had been gone through and valued, what then? If there was no son already working in the trade for a direct inheritance, I am assuming that just like today, things would have been sold off piecemeal.
I will say I don't think it's possible realistically to put a name to this. It's too rough and unrefined; yes, it looks Lehigh-ish or possibly eastern Berks, but I think that's about as much as that envelope can be pushed. To try to put a name to it is just pulling things out of thin air and that typically ends up with pure silliness.
I think is likely early 19th century, think Kuntz or John Rupp II type architecture.
The lock that's in it probably isn't so far off, especially if you could get a 'tit' welded on the tail and it blended in properly.
There are many people that can work on this for you but frankly I think Jack Brooks is pretty much who I would go to. He's not going to be cheap either, but it will be right and it will be undetectable. The issue here is how much you want to spend on a bare bones piece like this.
