The receiver of an AUG ( that huge aluminum pressure cast piece) is the registered firearm. The F90 practically ditches that and replaces it with a plastic clam shells like FN2000.
I think the argument is that the receiver is completely different, but it happens that the stock, trigger, and bolt groups are of the same design.
is it going to fly? The precedents produced by the lab do not seem to be consistent and sometimes murky. So it is 50/50. By heritage, it comes from Aussie AUG even Lithgow admitted and advertised so. By technicality, the receiver is not an AUG - aluminum pressure cast, QD barrel feature..etc, i think it is patented. It is an AUG but also not an AUG.
Anyways, even if it is available, it will be confined to 5 rd AUG mag. There is no "nato stock" for it. Just because of this, X95 will have a huge leg above it.