I recall reading in a mid 80's Pontiac Magazine about the problems with identifying 9 t/a's. I would be willing to bet money that the article said that D80 code didn't mean it was a t/a. It only signified a rear spoiler, and there were a considerable number of non t/a cars produced with the D80 option.

Doesn't one of the packrats around here have a collection of Pontiac Mags? To help narrow down the search, it would have appeared sometime around 86 to 89, and if I had to narrow it down to a single year, I'd start with 1988.