Does such a list of these exist and/or has anyone kept track; perhaps a record created by Norm that detailed his collection?
Ian, Norm Flayderman was an honored guest at our local gun club (Palm Beach Gun Collectors' Club now known as "Palm Beach Historical Arms Collectors Assn.") at every Christmas dinner in years past.
He and I entered into a few, in-depth "conversations" about his evaluation of antique firearms which excluded bore and mechanical function as a consideration in value.
As a master mechanic I argued (er ... "discussed") the mechanical condition and bore are equally, if not more important, as all other considerations when evaluating.
It was always difficult to ascertain what was his "personal" collection and what was his inventory for sale.
Other than the Flaydermans' Antique Guns price guide he printed mailers.
Watch ebay and other auction sites for Flayerman's (i think quarterly) printed sales offerings.
Next time you visit I'll show you about appx 20 of the mailers plus every edition of his price guide, personalized to me.
I pondered that your 6" American SN: 1707 might have possibly be listed in one of those old mailers but who knows how many decades ago. That would be a lengthy research project with no guarantee you will find it listed, however, you will learn much in the process of reading those old mailers.
Best Regards, Sal