Hello, A friend of mine acquired what may be an 1861 Springfield from his in-laws. It's in pretty bad shape; forearm has been cut down; and what looks like a repair to the wrist. The barrel has some faint signs of rifling in it, and looks like a .577 or .58 size bore, but is badly rusted. There are a series of numbers stamped on the tang and toe of the stock; which appear to be "28" and "96" and "26." Any idea if the numbers have significance for identifying the rifle? Thank you for any assistance you can provide.