Pre-sold iPhone 5 already sold out?

Carriers begin selling out of Sept. 21 delivery for Apple’s iPhone 5 [u]
[Via AppleInsider]

With Apple sold out of launch date inventory for the iPhone 5 in just over an hour, U.S. carriers AT&T and Verizon saw their estimated arrival dates also begin to slip past Sept. 21 as of Friday afternoon.

Hope this is not a sign of  manufacturing problems. MOst likely they are just rationing them so they have lots of phones at the physical launch.