The name on the lock could be indicative of a few different things.
It was (common) for the hardware stores that sold the locks (which were available to the general public - just walked into the hardware store and picked one up along with some rope or nails) to put their names on them. Or the importer may have marked the lock - that was also "common".
It may have also been engraved by the builder (but less likely) in either their name or the name of the customer that the gun was sold to.
The lock may well have originally been produced in England or Belgium. Both countries exported boat loads of parts to the US during that time period.
Well I am not much more than a hobby builder of BP longrifles, I would not be surprised if this rifle was built in Vermont or New York (upstate). It is indicative of the stock shape, decoration etc of the time frame when the locks were popular.
This does look a little more fancy than a typical "bought at the hardware store complete/finished rifle", but it is possible that's how it was acquired and not a "custom build" for the original owner.
I have seen a couple of rifles of similar vintage and style/apparent quality sell in the 1000-1500 buck range (built by a Canadian named Soper). Now this rifle could be worth much more if the builder turned out to be "someone" or somewhat less if this simply came from "Hellinghaus Hardware".
Without having someone actually look at the piece I wouldn't mess with it at all. You could shave significant value by messing around with it. If it turned out to simply be a "nice old gun" then perhaps it would be worth getting it into shooting condition (if safe enough) and enjoying it. But you don't want to "oil away" a couple grand by fiddling with a rare piece...