Dealer Part, Rock Auto is not likely to have it. The new number is 5M6Z-10C659-B, and I got mine from FordPartsGiant.com, but I have also used Tasca Parts.
They are ~$300+ ship. You should also consider doing the Blend Door Motor/Actuator (AL8Z-19E616-F) That new part number is supposed to be much more reliable than the older models. Replacing it is a PIA, but it is only ~$30 and is a common problem. Good video on replacing it: https://www.youtube.com/watch?v=QFtgRL_PAkE
Note: FordPartsGiant usually drop-ships from a Ford Dealer, Tasca is
a Ford Dealership.