Did People Tint Windows in mid - late 70s?

Just like it says. Did car guys tint their windows in the mid-late 70s? Im just curious as to when the trend started. I know we've discussed yes or no to tinting windows on here and its all personal preference. But would it be acceptable to lightly (maybe 20%) tint them on a "period build" for that era?

20% is pretty Dark, Its the percent of light that shows through. Sow it lets 20% of the light in.