Nope, those are oldies. While that might seem like splitting hairs, you'll instantly discover the difference when you tune your radio to a classic rock station. You won't hear any 50's rock, but a whole lot of 70's and 80's guitar rock. Even Motley Crue is considered classic rock these days.
I wonder when 90's music will start creeping into classic rock playlists. And which bands will make it. I'm going to guess that for the most part it will only be the Big 4 of Grunge. Nirvana, Soundgarden, Pearl Jam and Alice in Chains. Teh song selection will be interesting too. I would be willing to bet that Soundgarden gets the most play as they sound more like classic rock bands than the others to me. Of course I'm biased, Soundgarden is one of my favorite bands.
The classic rock station in my area (WCBS FM 101.1 ) USED to play alot of 1950s rock tunes (along with 60s and 70s rock), But then all of the sudden decided that they weren't going to play 1950s tunes anymore (I cant recall the reason). Then they dumped the oldies format: