Get with your dealerperson immediately and tell him you now have the X-Plan pin and want change the order to an X-Plan deal. He should process a "change order" transaction to indicate an X-Plan order.
However, it is not required that a dealer sell you a vehicle under X-Plan. If he gives you any static about changing the order to an X-Plan order, then cancel the order and find another dealer to order it from. But the first words out of your mouth should be "will you accept an X-Plan deal for a new Superduty pickup?" 99 percent of the time the answer will be "yes". But it's the dealer's option, not yours.
If you have a trade-in, don't be surprized if the numbers all change on an X-Plan deal.
Unless your dealerperson knew you were in the process of obtaining an X-Plan PIN, you broke the rules by obtaining your X-Plan PIN
after you had discussed prices with your dealerperson. So don't be too hardheaded if your dealerperson doesn't want to cooperate. The person who gave you the PIN could get in trouble with Ford.