I remember the terms "Heavy Rock" and "Hard Rock" as being essentially from the '70s, then sometime in the early '80s (following the NWOBHM, launch of Kerrang! etc) "Metal" became the blanket term. And that did include AC/DC, Gn'R, even Def Leppard! I don't remember even hearing the term "Classic Rock" until many years later.
You didn't hear "classic Rock" till after 2000, or maybe when classic rock magazine launched
It was all post grunge and Nu - metal and journos started to refer to the previos waves (60s,70s and 80s as classic)
But you are right - even Bon Jovi etc got called Heavy Metal and featured on Headbangers Ball
Back then (1980) the only bands that were really heavy (or unlistenable depending on your point of view ) were the likes of Venom and Motorhead until in about 1983 we started to hear of bands like Metallica, Anthrax etc and they got called Thrash Metal.
And all those 80s bands with spandex pants, pointy guitars and big hair (like Poison, Motley, Ratt, WASP, and even Skid Row) tended to get called "glam rock" (an echo from the 70s) - it was only really about 1989/90 as Grunge was coming in that the term "Hair Metal tended to get used and by that time it was getting phased out.
And you didn't have "vintage electric guitars" until the mid 80s either - you just tended to have a pre-CBS strat or a 59 Les Paul