Typically, wrong email address entered, email going to spam are the 2 big ones. If they correct the email address it won't trigger the initial order submitted email but you will get all future communications.
Not sure how they will stop it right on 1966 orders. My assumption is that when they have received 1966 Limited orders they will not allow dealers to order one. They probably will have a balance out on that trim when they hit that many orders.