I’m surprised there’s an FFL that was unsure about legality of transferring a 59/66.
So was I!
I did my due diligence on the legality of it before I made the offer to buy it - I, and the seller were kinda blindsided by the hick-up.
The same thing happened to another member and I. I told the FFL (but that there was an exception for the original fixed magazine) to hang onto it until he got assurance so the seller could go on his way. Got a call the same day or the next to come pick it up.