The actual wording of the law, and the way it was interpreted when I was young was that a person who does not hold an FFL may not make a firearm with the intention of selling it, but after making it, they could change their mind and then sell it.

Since, the BATF decided to interpret the prohibition as a thought-crime, enforcing a prohibition making such sales illegal, since like The Shadow, they know what lurks in the hearts of men.

The one transfer which has not yet been tested in the courts to my knowledge is an individual having made firearms, passing away, then leaving them in their will to their heirs....