Actually, he required a Kentucky state ID because it is a federal felony for him to transfer a gun to someone from a different state. It is legal for him to sell a long gun (but NOT a handgun) to someone from a neighboring state, but the actual physical transfer has to take place in that state, and he may have decided not to bother with that.
Please learn the difference between and clip and a magazine.
Those safety rules are paramount. I use Jeff Cooper’s Four Rules.