Good question and I don't know any better than you do, but I would like to know, so OST.
I'd love to stumble into an affordable (bwah hahaha) complete example of this rifle for my half-baked attempt at a collection of the 1800s .45-70 bolt rifles. After a couple of decades, it's a bubba'd up Remington Keene, Remington Lee and two 3rd Model Winchester Hotchkiss, so I guess you could say that I'm flying along at the pace my username would suggest.