Some many cars back then had vinyl tops added.
Yep. Guy at work here has a 72 Challenger with 1/2 vinyl top. I am not a fan of vinyl tops to begin with, and the half ones just don't do anything for me.
Also, about 12 years ago there was a Dodge Charger 500 (flush glass and headlights) that was in Mopar Nats parts swap area that had a half top installed. IIRC it also had those little fuzzy balls hanging along the top of the wind shield on the inside. So they were definitely a thing at some point in time.