I think the sampling we have is so small, provenance is so scarce, and early gunsmiths in the colonies probably varied so much in their backgrounds and styles that it is hazardous to rank the "early-ness" of any stack of early rifles. An "early" rifle that is out of the ordinary is more likely to be considered "quite early", when it might just have been a later oddity that nobody used as a template for subsequent builds.
Most of us who are particularly crazy for early pieces have our tentative dates for each of the "early ones". For me the Musician's rifle's provenance wins me over to the scratched date, though the 2 piece hinged box kind of makes me a little queasy about that. There are some early rifles tentatively dated to the 1760's that I don't "get" because they look like evolved longrifles, not "roots" guns.
The BBR looks like an anomaly but the cheekpiece design is similar to that of Tom Curran's bench copy of an unidentified plain rifle tentatively dating to the Revolutionary War period. That suggests the BBR was not an evolutionary dead end, or that it had some cousins or nieces or something. I find it easier to study and think about if I forget it has a brass barrel.
