Sounds interesting, do you need one to work in a sporting goods business that already sells firearms, or does the store itself carry it? Where can one get more info on them?
Sorry, I don’t remember the answer to that one offhand (been a long time). I would guess that the BATFE has a manual or other information resource on the Web for dealers, though. Back in the ‘70s, a hardcopy manual was published. It was easy to obtain.