If Universal has the same promotion, then most likely yes. Just remember that you will only be credited to the Universal promotion price when you upgrade, if you are referring to the buy 2 get 2 deal.
We upgraded Undercover Tourist promo tickets in April and it was fine. They applied the purchase price to the cost of the AP (they know how much you paid just by scanning the ticket). It worked fine, but it was really pointless since there was no cost savings. If you know you are going to get an AP just buy direct from Universal. Save the hassle.