That's what I'm starting to think. I did some more searching after I posted. I have a fastback that has a 1 under the X on the fender tag. On this website:
1967-1968 Mopar Fender Tag Decoder, Chrysler, Dodge, Plymouth That shows as Tinted Glass (All). I am assuming that if there is nothing under the X, then the car had clear glass as standard
Robert.