[kevinr1970]

I have an '85 GMC High Sierra that has power locks, windows, CC and air.
But it has what I would consider the lower end door panels (no pull straps), no door carpet, no headliner or any of the interior roof trim. The kick panels only cover the area around where the vents come through the cab.
Also, The outside trim that wraps around the body is black and it does not have any tailgate trim (the brushed stainless panel).

I just bought an '86 GMC Sierra Classic (the equivalent of a Silverado) and it has air and CC, but no power locks or windows.
I has the high end door panels (with pull straps and a carpeted insert), a fabric headliner, carpet on the lower doors, the kick panels go all the way to the floor, etc.
On the outside it has the chrome trim that wraps around the body and the brushed stainless tailgate panel.

Other people here are more knowledgable than me (like ElGracho) but I think I am pretty correct on the following:
Silverado (Sierra Classic) got you the nicer door panels, carpet standard, headliner standard, chrome trim and tailgate band standard and things like dual headlights standard.
There were also option packages you could buy that included different options like power options, CC, AC, etc.
And I think you could probably order just aboout any different option on a truck that you wanted to pay for.