Back glass
 

What would the back glass on my 68 GTO with ac be? Clear, green tint ?

It could be either, soft ray (green tint) of the windshield was mandatory with AC but soft ray for all windows was optional with or without AC. To be correct your back glass should match your side glass.

Are you trying to stay 100% correct ? I ordered a smoked glass kit for my 68 and it looks BA with the solar paint . It’s like a new car tint . Does what it’s supposed to do to , less glare and cooler .

hmmm didnt realize that ac 68-9 gto could have clear side and rear glass
the couple dozen ac cars I have had all had sof ray tint
good to know

Over 90% of AC cars had all windows with Soft-Ray glass but only the windshield Soft-Ray was mandatory with AC.
Another glass tidbit starting in 1970 was that the rear defroster option (wires in rear glass, as opposed to blower defogger) was only manufactured on Soft-Ray glass so if you ordered the option without ordering any soft-ray you’d have a clear windshield and side windows but a Soft-Ray rear glass. Depending which Soft-Ray option you order with the defroster you could also have just windshield and rear glass or all windows Soft-Ray.