In regard to the musician rifle, it is too early and too European (imho) to point toward any area of the colonies. I'd say it frankly could have been made anywhere a German-trained gunstocker settled.
The rifle at rock ford as best I can tell is being placed as a Lancaster gun because (1) it has a straight 'triangular' stock and (2) the daisy box. I think the 1770 dating is silly IF that box is first work. Not much more to say.
I'd love to see a very clear tracing of the signature remnant and then try to "fill in the blanks." Believably, without stretching credibility. Maybe it can be done, maybe it can't. Other than the purported interpretation of the signature and a non-step stock, I see absolutely nothing about the rock ford gun that relates to the musician rifle.