Here is an ad from Laughlin that appeared in the March 15, 1979 issue of Sports Collectors Digest, and explains that the 1971-1977 cards were done for a promotion with Good Humor. The original set of 68 cards was reprinted and the additional 7 cards were created to bring the set up to date for the summer of 1978. Bob wasn't lying when he said these were a "good investment"!
http://fleersticker.blogspot.com/201...s-mystery.html