That's only for rifles bought at retail from an FFL. If it was sold between individuals that's most likely the end of the trail, especially if the person who originally bought it is dead which is very likely the case for this one if I had to guess. It could have been the shooter's grandpa's or even great grandpa's hunting rifle, and there's no guarantee that their grandpa bought it from an FFL
After WW2 there was a massive surplus of undesirable rifles. People would buy these, 'bubba' them, then trade them, sell them, or just give them away when they got bored with them. Up through the 90s and even in the 2000s you could buy 'sporterized' surplus for basically nothing. These rifles were modified from their original military configurations in the hopes of making them more desirable to consumers. Lightweight polymer stocks with recoil pads to make them easier to lug through the woods, modernized optics mounts, ergonomic tweaks like adjusting the throw angles on the bolts, swapping the caliber to more common types, stuff like that