I have seen 68 mats glued down yellow glue brushed on trunk floor in certain spots to hold mat in place on a unmolested KR vert anyway. Never seen any sign of glue on factory mats in 69-70 Dearborn anyway so the glue thing may depend on the plant. I have had several used trunk mats over the years & when trying to clean them they had glue on the bottom side of the mats so some were glued down from factory. Decklid weatherstripping was glued on bottom of decklid since decklid was painted in the car so extra glue dripped off decklid onto trunk floor usually from front lower corners when decklid was open. But on a Shelby decklid was added much later so the dryed glue was already there under the mat from the steel decklid . I would think on a shelby fiberglass decklid aosmith would have glued weatherstipping on bottom decklid before bolting on car. I drip some yellow glue back on trunk floor in areas I usually see signs of glue on unrestored (Dearborn cars anyway) when I glue weatherstripping on bottom decklid as I often wondered if ford wanted some extra glue from weatherstripping install (or didn't care) if glue fell on trunk floor as the glue would help hold trunkmat in place.