The black looks like Buffalo horn, I use that for ferrules and butt caps.
I also use antler for both too. My first choice is Coues deer, I believe it is a type of Whitetail.
Denser though. Your ferrules look great.
So many companies made these. Figuring out who, may be nearly impossible.
It does not look like anything I have seen from The big companies that I know of.
It is nice and not homemade, I am fairly sure of that.