Rich,
I am helping a friend restore his 67 Nebraska Centennial addition. It is a C code 289 D code Acapulco blue W/ C4 auto and PS. It is also a Sport Sprint. There is nothing on the Marti report indicating any thing special about the car other than the Sport Sprint. The car has been in my home town Weeping Water, NE. since new and I know the original owner who said that the dealer told them it is a Centennial addition and gave them a Nebraska Centennial medallion when they purchased the car.
Where is the car you are speaking of? I am not sure that the special addition add much value beyond the Sports Sprint. It would be important that the medallion was included. It was a neat regional promotion.
Marty