You have a difficult problem I5. The simplest answer I can offer is, "I have never seen an unprovenanced H&A shotgun sell outside of your ins carriers minimum bracket".
When I see an H&A, I think tool, not art.
I think Ethan Allen thought that way too.

And a whole bunch of historical societies in the northeast.
I see most of the shotguns produced in the upper east as links in a continuous manufacturing chain, feeding a growing westward expansion. Symbols of growth and necessity, not art.

There's probably a great family tale stemming from Mrs. Johnson's husbands patent's, but I have not read it. Occasionally, someone mentions them though.

Out there doing it best I can.