Rich-Thank you for posting the photos of what is a truly grand Hudson Valley Fowler, and an early one at that. There are not many of these left, and in truth, there probably weren't that many to begin with; so, this one is even more important.
It has all of the high art features that you could want on this type of gun. As you stated, the sideplate is classic and goes very well with the rest of the ornamentation on this gun. The maker chose good maple to stock his gun. Is that a Spanish proof mark on the top barrel flat?
It appears to be in 'as found' condition and it must have seen a period of military service since it has a musket top barrel band with military iron ramrod, and bayonet lug on top. Wonder if the barrel has been shortened? can't tell from the photographs; the really early ones had barrels so long that you could reach out and touch your target.
It would be nice if someone could get a grant to travel around the country to museums to gain access to arms of interest and to fully document such pieces. There must be hundreds of large and small public and private insitutions across the nation. With such a program underway, many hyper private, closet collectors might be inspired to participate, as well. What an addition all of that data would be to the ALR Library. Thanks again.
Dick