Send an email with photo to Leaf Inc. (Payday) PR department telling them the story and asking them about it. Ask them if your nickel could be a nickel from one of their 1988 Payday bars. Their records might indicate how they were packaged back then.
"In 1988, Hollywood Brands, the maker of Payday and Zero, was purchased from Sara Lee by Huhtamäki Oyj and became part of Leaf, Inc.[5][6].[5]"
Hershey then bought it in 1996. I don't know if all candy bar records would go to the new owners. If so, then Hershey PR dept might be a good source.
http://en.wikipedia.org/wiki/Leaf_Candy_CompanyPayDay was first introduced in 1932 by Frank Martoccio. Martoccio founded the F.A. Martoccio Macaroni Company, and also later served as head of the Hollywood Candy Company. Hollywood also produced the ZERO bar.[1] Hollywood moved to Centralia, Illinois, in 1938. In 1967, the Martoccio family sold Hollywood Brands to Consolidated Foods, which later became Sara Lee. Fire destroyed the Centralia plant in 1980. Production of the PayDay bar continued with help from the L.S. Heath and Sons Company until a new facility could be constructed. In 1988, Hollywood Brands was acquired by the Leaf Candy Company, then later became part of The Hershey Company in 1996.
Keep us posted.