This picture shows the portion of the film that talks about the Time Capsule Burial Ceremony. This time capsule was supposed to be opened 50 years in the future, but I don't remember anyone at the Speedway doing anything about it back in 2017. Perhaps the time capsule was lost and/or destroyed during construction/rehab of the facilities in the intervening years.
The first picture shows Chevrolet General Manager Elliott "Pete" Estes holding a postcard of the 1967 Camaro RS/SS convertible Indy Pace Car that he would place inside the time capsule.
The 2nd & 3rd pictures show what the postcard looked like (worthpoint.com)