In fact, if you're interested, there's a Fallout 3 mod called More Where That Came From which adds up to 100 similar-era songs to GNR's playlist. They're all MP3 format too.
I very much wanted to use that as GNR gets pretty painful after a while, but couldn't get it to work. There was some sort of a warbling thing going on. I'm sure I can thank Creative's wonderful Win7 support for that.
Anyway, I'm amazed that I actually recognize some of this music as I haven't played FO1/2 since they were new.