There are a lot of mysteries when it comes to these rifles - just when you think you begin to see some sort of pattern or consistency that allows you to begin to understand how/when and from whom a certain local style evolved, a piece turns up that flips all these concepts over and makes you rethink everything. While it is easy to see a progression from the work of the Beans and others in the 1830 era toward the later rifles from the same region by gunmakers like Lawing , we don't really know how early that general style began to appear. Perhaps the biggest missing pieces of the puzzle are documented pieces by a few more of the gunmakers we know were working in the area in the 1770-1790 era. Most of us would love to see what Russell Bean was making in the late 1780s and 1790s. And while we tend to think of gunsmiths like Joseph Bogle bringing outside style influences into the region, which they of course did, it was not necessarily all one-way. Even in the relatively early period before 1800, gunmakers moving into the region were also possibly equally influenced by a gunmaking culture and style prefrences that were already there in the mountain region and beyond. I am not saying that they were making deep crescent skinny buttplates and over the comb tangs in the region that early, but by 1790-1800 there might have already been some general style features unique to the region that were fairly different from what you would see on rifles being made in places like Salem, Winchester or points north.
Guy