Not to get off of the beaten path, but wasn't the 2v 390 very "uncommon"? As alot of folks just assumed to go with the 4v set up? I remember Jon Enyeart saying how "rare" it was to find the 2v carb for that 68' engine?? maybe I'm wrong??
If the guy has the original carb I would snag that too.
According to Kevin Marti's "Mustang by the Numbers" book, for 1968, out of the 317,423 Mustangs produced, there were only 733 of the 390 2V produced (all with the C6 Transmission}, and 10,651 with the 390 4V (5800 with the wide ratio 4 speed manual, 4850 with the C6 automatic, and 1 with the C4 automatic).
So, if 0.2% would be considered "uncommon", yes.
Bob