There's no doubt about this being the genuine article.  The brass squire shanked tacks have been in this stock since it's original period of use. The musket itself is a cut-down mdl.1861 Springfield dated 1862 that was captured by the Indians.  I beleive the gun was cut-down before the Indians acquired it has the workmanship is much better than the Indians would have used .  In particular the filling of the front barrel spring with a wooden inlay. The wrist has been Indian repaired many times in it's life with wood screws and hide wrapping which is now missing.  However, you can still see the darkened discoloration in the wood where the hide was wrapped.  A real Indian owned gun that's early enough to have seen much Western use including the Little Big Horn.