50 cal muzzleloader

The story about this is it was hidden in some guys drywall and he passed away. His son knew it was in the wall so he dug it out. He said as far as he knows it worked when it was hidden away, but he couldn't keep it because he didn't have a pal. It's 5 feet long with octagon barrel  barrel.And beautiful tiger, striped wood and brass. Not sure about who the maker was there's no stamps or nothing. The only thing the son knew about it was it was a 50 cal. I'm not sure how these things work so I'm not gonna fire it, but I was told it works. Buyer pays for shipping.