for example - GG's "1970 'Cuda book" shows:

* 16,710 US Spec. 'Cuda hardtops (BS23) at $3,164.00
** 2,072 with Air/Conditioning (H51) at $357.65
** 4,946 with tinted glass - ALL (G11) at $32.75
** 4,729 with tinted windshield (G15) at $20.40

..... and by 1970, if you ordered H51 "air conditioning" Chrysler would automatically add G11 "tinted glass - ALL" to your order unless you specifically NOTED G21 "clear glass" on the order form.

Chrysler and/or the dealer did not want to get stuck with a mistake: "OH, I thought that was included!" or "I forgot to check that box!" or "The salesman messed up, how do we fix this?".