They would have to waive the '86 ban on registering "new" full autos on the NFR. M14s are classified as machineguns. They could make a nice sum on the weapons though.And I don't think they're destroying them anymore. USMC has used some for the DMR, and isn't the M14 still the Navy's issue rifle?
I think I heard that the Navy has with drew them from general use but they may still be carried on some of the Subs.