Black Betty song by Jet

I could swear that the song "Black Betty" was released by the band Jet around 2008 or so on their Get Born album. Turns out it the track I "discovered" then dates from the 70s and a group called Ram Jam? That song is too bangin' for it not to have been in common rotation in the eighties along with The Centerfold song (Na na na na na na na na na na na na na na). Why can't I remember it from the 70s and 80s? I swear I don't remember the heavy banjo version by Spyderwick from the early 2000s until a few years back. There is a repeated lyric in that one that doesn't sound right either. I remember being surprised by the repeated lyric on the radio (I think it's "and she's always ready").