Gentlemen: The initials J R on the pistols thumb plate and the patchbox, recently posted, certainly weigh heavy in Rupp's favor, However, the pistol and rifle may have been made for the same person. And his initials may have been J R.
I think several various 'signature characteristics' need to be examined prior to an accurate attribution. As an example: Jacob Kuntz's use of a platform surrounding the breech tang is very similar to what we see on this pistol. In addition, the surround of the basket weave is identical to several Jacob Kuntz pistols extant. And the basket weave carving, itself, is not a simple task. Both Rupp and Kuntz basket weave techniques need to be studied You will also find parallel lines carved above the lock and below the lock mortise on both Rupp and Kuntz pistols. And something else to consider is the 'hen scratching' engraving found on many J. Kuntz rifles and pistols. Is it there on #21 ?
I believe someone with a greater talent than mine should post detailed pictures of number 21 along with detailed photos of known examples of pistols either signed or attributed to J. Kuntz. Then a time frame should be established in which both gunsmiths worked. As a starter, it is believed Jacob Kuntz learned the trade near Allentown before moving to Philadelphia in or near 1810 or 1811. It is entirely possible Kuntz apprenticed with Rupp several years before moving his shop to Philadelphia. I do not know when Rupp was active. A documented study, if not already done, would bring the maker of the unsifgned #21 pistol closer to a reasonable attribution. At the moment, it is my opinion #21 was made by Rupp, but it could also be an early J. Kuntz, made prior to his move to Philly. And it might have been made by Kuntz in the Rupp shop.
For now you have a superb Kentucky pistol courtesy of the Kentucky Rifle Foundation and its affiliate the Kentucky Rifle Association.
The challenge is to identify the maker and provide the collector/owner with at least an attribution based on fact and reasonable comparisons.
Think 'signature characteristics' . In this case the 'basket weave' will play a large role.
With respect, HIB