I agree the NW gun is a cheaper made gun. No engraving is the big time saver over the Carolina gun, not that the Carolina's engraving took any real time. All the Carolina engraving is about as crude as you'll ever see.
As far as stock architecture for a 50's dated NWG I'd lean towards 1750's english fowler architecture. The heel of the butt plate was also more rounded then the later ones that had a sharp 90* bend at the heel. I'd also keep the earlier guns a little slimmer in the stock in general.
I saw a very interesting gun that was connected in some way to the NWG a while ago. I didn't get any pictures as I was distracted by selling a gun, But I did get a quick look at it. Unfortunately by the time I sold my gun the guy had covered his table and left so I couldn't study the gun in depth. It had a 4' barrel of the identical pattern I use on my carolina guns, which is a direct copy of Reeves Goehrings "11 shilling" gun. It had british oval shaped proofs at the breech. The lock had an unbridled pan and a HBC tombstone fox stamp.It was undated if I recall correctly. The sideplate was a typical NWG sideplate. The trigger guard was a iron strap type just like a NWG butt it had a small cupped bow. The tang bolt went from the bottom, up and threaded into the barrel tang. The buttplate was a standard british fowler buttplate in brass, close to 5" tall by 2" wide, fairly nicely engraved. I don't recall if it had a thumb piece. The carving at the breech was very similar to the "Duncan gun" in Hamilton's book. I don't know where this gun exactly fit into HBC's gun orders, but I suspect it was what they called a "Chief's gun". I always disliked that term, but they used it.
I suspect you could have found the same gun in "Carolina gun territory" with the exchange of the cast NWG sideplate for the engraved carolina gun sideplate. It may not have been called a "Chief's gun" in the south, as I think the market catered to whites as well as Indians south of HBC territory. OK , I'll stop now. :surrender: :haha: