This horn looks strangely like some of the contemporary work done by Sylvan Hart, also known as "Buckskin Bill". He lived on a remote stretch of the Salmon River, and was more hermit than mountain man. His work featured a lot of forged metal. Practicality, and period correctness, were not part of his esthetic, the odder, and more exotic the better, was his style.
I have a book printed by Peterson Press that was written about Sylvan Hart. I use it as a guide post. When I build something I think is out of this world, I quickly dig out that book, and check to see if there is something similar in it. If I find something similar, I scrap the project.
Hungry Horse