Is there any scale or hammer marks on the bottom of the barrel? Are there any open or filled dove tails on the barrel? Lastly, do you see any grind marks (faint) on the bottom of the barrel?
It just may be that the barrel came from a barrel mill, a production barrel so to speak, just like what we can purchase from modern day makers.
If it were re-purposed (a common practice) the barrel will often show where older dovetails were, sometimes filled, sometimes not. And it also may be that the plug is forged, where as the barrel was not (I have a couple of those)
Then again, it just may be that the barrel was always a halfstock used barrel, it is hard to tell from just the pictures provided.
Orgin? Could be anywhere from the east coast to just about anywhere. If it was a rifle made in Ohio the maker should (but that's not always the case) be indexed somewhere in one of the Ohio Longrifle series.