I thought the same.Wow, I never realized it was a non a/c truck. Surprising for 1991, I would have assumed by then a/c would be like p/s and p/b - pretty much non negotiable.
I had a 91 single rear cc with the 350/4l80e/205 and it was manual windows, manual locks, rubber floor mats and a/c.
Didn't know they had non a/c.
It was rusted more than worth saving so I sold the engine trans tcase to new Mexico.
Can't remember his name now, a member here but I believe he still has it and would sell it.