Yes, but they most likely will sit at the local shipping depots until 4/3, just like the 3GS pre-orders.
"When the iPhone 3GS shipped last year, Apple commanded UPS to hold on to the packages until launch day, even if they were sitting there, ready and waiting in your local branch like gifts under a Christmas tree."
"When the iPhone 3GS shipped last year, Apple commanded UPS to hold on to the packages until launch day, even if they were sitting there, ready and waiting in your local branch like gifts under a Christmas tree."