I don't know anything about the insurance but the individual who currently holds the lease for that property had JUST acquired it earlier this year for 3.2 billion dollars, how ironic is that?
He has, however, made a personal committment that the towers will be rebuilt. It really is the only sensible thing. The memorial for the Oklahoma city bombing was one thing, the property was owned by the government already, but do you really think someone who just dropped 3.2 billion dollars on a ONE HUNDRED year lease is going to let it sit there with a memorial on it? Hell no! Of course he's going to rebuild it, insurance or not, because without a building on it it isn't going to make any money to pay the mortgage on that humongous freaking loan.