I wonder if your gun shop is thinking of the requirement of notifying the ATF of "multiple purchases" within so many days of a previous purchase. My local FFL told me of his requirement of having to do extra paperwork if you purchase more than one gun in a week. (Or maybe it's a 5 day work week.) Either way, to prevent him from having to do extra paperwork, and possibly causing the ATF to look at him or me more closely, waiting a few days for another purchase is a small inconvenience to me,, but not a problem.
Either way,, it sounds like you have a nice gun coming at a good price.