I guess there could be a way to make a Carrier ID that you have to mount that serves as a scanner and then FL hook certain missiles to be in stock like.. 70 or 500. and then only carriers can purchase it because they have the carrier ID in addition to having an regular ID, but seriously?...
can't you just purchase missiles, missile launcher and jettison them both, so the other ship can tractor it all in. Now he can hold 40 missiles he can't use. He can give them to you.