OF COURSE there was window tint back then. I remember a couple of guys in our small town had their windows tinted. I'm SURE J.C. Whitney/ Warshosky sold it
One of the "Wells" brothers had a NICE dark dark green 55 Chev with "chromeees" and tinted windows that just looked boss as hell. It would have been a proud addition to "American Graffiti" 264 4bbl, 4 speed.