You have no reason to believe that is the case. Usually it isn’t. Information is reaevaluated all of the time and reclassified accordingly. This is extrememly common. Source: I am a military scientist.

Nuclear weapons, fully functioning tanks, bazookas, hand grenades, ect...

Most guns are manufactured and sold in the U.S. Most guns smuggled into other countries come from the U.S. Even still, in those countries it is very difficult and expensive to get a gun especially on a whim. It is more difficult to smuggle guns…