question for insiders: schedules

May I aks you insiders a question?!
I come from Germany and I've never been to NCY before and according to that I've no experience with Broadway-schedules. Here is my question: If the previews of 'cat on a hot tin roof' start february 12 and the official opening is on march 6, can I be sure that they will also play during february 21 to 25.? The reason why I ask is that I need to book a flight to the United States as soon as possible to get the early bird prices, if I want to see the play in february 2008. I just saw a very good offer and I want to book it!
Thank you very much in advance for your reply!

Thanks a lot! Now I just have to wait until the cast will be announced, because my trip to New York depends on the fact if Phylicia Rashad does or does not appear on that show.