Probably typical bureaucratic red tape of a government agency to hold on to them. Nobody could make a decision on what to do with them. Since they are NFA items, it's been easier to just keep them stored, than try to sell them. Now with pre 86 hardware bringing such a high price tag someone finally pulled the right strings and found a way to make a effective business decision. Or the guy that kept them around as there departmental collection retired. There is a department I know of, with that particular sheriff there, there is a nice collection of NFA goodies that's pretty much the departments toy collection. I bet that nfa hardware won't be maintained when he retires.