I think perhaps two Boone rifles with some degree of provenance have survived, but they remain in private hands where they are not seen by collectors, and perhaps not shared with others due to fear of theft. Several years ago a bag & horn set with some degree of provenance to Boone briefly showed up [I saw pictures of it, and it looked like it had some possibility of being legitimate], but then it "disappeared" within the family when other members realized how much it might be worth. Unfortunately, items that disappear like that, often disappear for good.
One of the big problems is that, with famous people such as Boone or Kenton, a lot of "wanna be" items get attributed to them, which makes people more suspicious of other items with a claimed connection. A lot of old provenances have verbal rememberances as part of them, and other small holes in the linage that might be questioned if closely examined. So real items at times can't stand the scrutiny of today's questioners. We seem to give a little more "slack" to provenances on items belonging to less famous people. Shelby Gallien