This sounds a bit crazy because I was the biggest Zeppelin fan in the mid 70s and started playing guitar in the late 70s but other than Stairway (all beginners learned that) I didn't really want to learn/play any of Slim Jim's electric stuff. I did learn some of the acoustic stuff.
A year or two ago I did learn Rain Song, that one is different (the first and maybe only? ballad). But I never play it because of the tuning (I know it can be faked in standard but it doesn't sound right to me).