No amnesty is like saying it is better to have unpapered war trophies floating about with no incentive to report loss or theft, rather than allow heirs to register and legitimize a war trophy of a deceased vet.
Which is exactly what Hughes does, and with no, zero, none, not ever fingers-crossed, way to "legitimize" anything, even WWI or Span-Am or KW or VN bring-backs.
Which, to my thinking, is the answer to OP's question.
We will see an amnesty only after some highly decorated war hero passes, and the heirs of that hero are clapped into irons for merely trying to sort through the estate.
Further, to really bite into "modern" newsthink, it will be the veteran heirs of a passed war hero tossed into jail. "[War]
Vet Jailed for [Relative's]
Machine Gun" would be a "selling" headline.
However, given the lily-liverred nature of our modern congress-creatures, I'd not be surprised if the Amnesty would only allow for transfer to museums and not to the 'general' NFR.