I would wager the real number is a whole lot higher and will never be known. How many handed down guns are in the back of closets or safes that nobody acknowledges having?
Yup, Over at a friend's house warming a bit back and getting a tour of the new place and, bam, closet with a stack of rifles and shotguns. His from when he was a kid, dad's, grandpa's. Had forgotten he even had them until they bought the new place and moved.