A dealer tried this with me. I shipped a rifle to an FFL dealer in another state. It was an even trade between me and another person. The other person shipped his rifle to my FFL dealer. My dealer had no problem with it, received the rifle and transfered it to me. His dealer said he had to send the one I shipped back because I am not an FFL.
Trade was over in my opinion. I told him I shipped my rifle to him in a legal manner with a copy of my drivers license as allowed by Federal law and there were no laws in either state that prohibited an unlicensed person to ship a rifle directly to an 01 FFL. My dealer had already transfered the other rifle to me. Trade was a done deal. I told him if he shipped the rifle back to me I would refuse the shipment. I instructed him to contact his local ATF representive if he wished to take further action and to feel free to have him call me.
The man I traded with emailed and said the dealer did call his ATF contact, but found he had no recourse against me, so subsequently logged the rifle into his bound book using my drivers license and did the transfer as was allowed by law.