It is going to be very confusing if the ban is not reinstated. I am certainly not saying it should but many states like New York and Callifornia have passed mirror laws without the expiration (yes I made up the term mirror law). So for example if it is not reinstated. A ar that I buy today will be able to be modified to a collapsable stock after sept 04 if I live in vermont, not in New York, but I could not take that rifle to New York becuase they have a state ban. Standard caps could only be sold to certain state (like NJ was before). To compound that most of the state laws do not have requirements for marking the receiver so how will we know when the federal ban expires other than cerail number when and where things are legal. Thirdly what if a police officer buys now a m4 clone with a 16 inch barrell for duty use with his own money. They ban expires and he wants to sell it to a civilian. There is no reason at that point the civillian can't own it but it will be marked for police only, same with mags.
TO confuse it more what if the law is reinstated but there is a lapsa of 1 day to a year between the activation of the new law. Delayed for some reason etc. In that one day you would see allot of post ban stuff beeing converted to preban configeration and everything up to that point is now pre new ban and you can convert it.
Ahh I hope the ban just expires peacefully maybe do to something else more troubling going on in the world and it will all go away. Very confusing to think about though and people will just be stuck with strange state laws, like my former state of NY. God I love Vermont.