As if the expert talks and demonstrations given by the dedicated rangers at Wright Brothers National Memorial were not enough of an attraction for repeat visitors, the park ordered a modification of their cancellation in June 2008.  The new stamp says: 

Wright Brothers NM/Kill Devil Hills

Check your collection:  The old one read:

Wright Bros. Nat’l Memorial/Kill Devil Hills, NC

No word on if the old cancellation (as well as the 2003 centennial cancellation) are still available at the park, but it’s a good bet that they are not.  (That won’t stop the most passionate Passport fans from asking, of course. You never know!)