This is the 44XL. Several companies offered loadings. Marble loaded the 44WCF with a round ball and called it the Game Getter after their gun.
This is the 1st version with sights. Later versions were chambered for 410.
A later version
These came with barrels of various lengths, some of which are illegal today without a stamp.
Many makers offered guns chambered for the 44XL. Here is my 44XL sxs.
You are correct. Keep the gun at home until the proper paperwork can be produced. If he had the firing pin removed and the barrel plugged, it would still be a family heirloom and be legal.
Pete