Hard to give good advice without good pics...
A lot of folks have an "old" muzzleloader that is from the 1950s...This would be treated much differently than a gun made in the 1850s...
The stock is where the maker "makes his mark" or uses his artistic ability and many can identify rifle makers by the stock alone...The barrels, locks and other furniture are actually less significant in valuing a gun vs the stock...
So, if it is indeed an original the less done to the stock the better...If it was made in the 1950s and sold as an original your best bet might be to restock it if the barrel is worth seeing additional service...