Are we allowed to do it?

I need your comments here. We are buying a new house in Illinois. However, our escrow closing on Nov. 30 and we are wondering if delaying the closing until Dec.15th would make us eligible for the $6,500 repeat homebuyer tax credit. The tax credit details are not announced yet, so we do not know for sure about credit. We would like to know any perspectives. We purchased the first house five years ago and were trading up our new house and this will be our principal residence. What is the best thing to do about it? Are we allowed to do this way?