I asked this same question back in 2018 at the York County rifle symposium during the question and answer period, and did not get much of an answer. A while later a well known collector approached me and asked if I got my answer yet. I said "No", and asked him the difference when carving and patchbox design was taken out of the mix. He said " There is not a whole lot of difference". I asked this question of a current builder of rifles who has built both styles and he said he thought the York guns may be slimmer, but when I was looking at the guns on display at the symposium, there were several earlier guns (an Eister comes to mind), that had an earlier style thick wrist and butt stock. So, as in the Lancaster guns, time frame may dictate this. Any specific York details that can be added would be appreciated.
Thanks, Roland