When you call make sure that they have the the tickets you need (specify DC or not) and if they have the GIFT CARDS available.
If they run out of DD (which they did when I went yesterday), you can still exchange the gift cards for DD later in your trip, at another TDS, or just use when you get home (TDS), etc.
If they run out of gift cards, they WILL NOT give you DD, rain checks, credit, or use limited edition Monster, Inc. gift cards. You will then be buying tickets from TDS with no advantages over WDW - unless they still have t-shirts left.
Good luck! And have fun next week!