Be prepared to sell them again.
I'd run out of fingers and toes if I tried to count the number of pre-1898 Afghani weapons that were given the "okay" by customs, only to tell the service member "no [expletive] way" when it was time to actually send them home.
We even had one guy spend two and a half days in lockup, while the MPs and special investigators poked around to see if they could stick him for 'weapons smuggling'.
He tried to send two archaic flintlocks home, and even had everything "cleared" by customs.