We had the same discussions (in the UK at least) about deliveries of the first iPad...
The AppleStore page showed "Ships By [launch date]" which got a lot of people worried that they would get it after the launch date (if it was shipped on launch day, a Friday, a next-working-day delivery would be Monday). In the end, most people (me included) took delivery of their pre-ordered iPad the day before the official launch day.
Apple work closely with the couriers to control when their pre-ordered launch products are delivered to customers. There was speculation that the large number of iPads to be delivered on launch day was going to cause the couriers logistical problems, so (it was thought) Apple authorised the start of delivery a day early (to give the couriers two days to make deliveries).
Hopefully the same might happen this time.