I spoke to a guy a number of years back who was a descendant and had done quite a bit fo family research, but he didn;t have anything really new either. Apparently very hard to turn stuff up.
Some people have speculated that "Jacob Dubbs" and the J. Daub who signed a Bucks-looking gun or two (w/ side opener) were the same guy. I don;t know. I know I have some pictures somewhere of a later signed J. Daub rifle along with a much earlier (big stocked) piece that seems pretty obviously by the same guy, but I'll have to find them. The early one had some really bad restoration work done but I distinctly remember that scratched on the cheek side was a 177x date and the words, 'I am not afraid" although who knows if it was legitimate. I can't remember who sent them to me, so not sure if I am supposed to keep a lid on them or not. I guess I'll wait a bit and see if anyone pops up and yells at me!