Quote:

I restored a 1971 Cuda which was coded with both H51 and G21.
Which decodes as:
H51 Air Conditioning w/ft heater
G21 Clear Glass with A/C

This is according to GG little white book.
From this I ASSumed that A/C came standard with tinted glass but if you wanted to delete it you would need to choose G21



Basically you are correct.

This is straight from the 71 Barracuda coding guide:

G11 Tinted glass-all windows. Remarks: Recommended with AC

G15 Tinted windshield. no remarks

G21 Clear glass-all windows. Remarks: To be used only when tinted glass is not desired with AC.

All of the Barracuda models show the three codes above with an "E" in the columns, which means "extra".

Sounds like if you ordered AC, and didn't want tint, but forgot to check the G21 code, they put G11 full tint on the car, and also charged you for it. It wasn't included in the AC price. I have an original 73 Challenger window sticker, and both items have a separate charge.

I'd be willing to bet that 99% of the sales bank and dealer ordered cars had tint with AC. The AC cars with no tint were probably customer ordered sold cars, and the buyer was trying to save a few bucks.