I did a search and couldn't find anything conclusive. According to 1992 Pontiac sales literature, "Structural adhesive was added to enhance body harmonics."

Has anybody found it was used in 1991 too? Were any bulletins issued during the 1991 model year that denote when it was first used in production?

 

The first use I recall of panel bond from the manufacturer was on Aerostar vans. They used it to hold the roof on. Can't remember what year they came out. I see it everywhere now.