IF an NFA firearm is a Curio & Relic, and you hold a C&R FFL, it can be transferred directly from the seller to you. Without going thru a Dealer. HOWEVER- you still need to do all of the transfer paperwork with the ATF, pay the fees, give them your first born child, etc. When you have the paperwork in hand, with the canceled stamp, THEN it can be shipped directly to you.
Form 4 is, IIRC, for transfer of an NFA arm within a state. As opposed to interstate.