1968 Nova's and Camaro's used the same seal, P/N 3937126, with a note to "Cut as required" on the Nova. No listing of ANY seals for 67 and no listing for the Radiator Support seal for 69, although there are other seals listed for "68 and 69".
I looked in the Price and Accessories Schedule, and P/N 3937126 was only used on Chevrolet cars. What's really interesting is that the 68 A.I.M. has a note (#10) for the seal to "Remove backing for installation", indicating that the seal used double sided tape to apply to the support.
Someone will have to take a look at the 67 A.I.M. to see what (if any) parts were used, and the 69 A.I.M. to see if the P/N is the same as the 68.