Vinyl pressing mistakes


Ever seen an LP with the the wrong label? I have an old LP that has a different artist/album side pressed on the b side. I listened to the a side of 'Blue Man' by Steve Khan.... flipped it over and Tim Wiesebeg/Dan Fogalberg (sp?)'Power of Gold' or some such nonsence starts playing... surprise! How common are these mistakes? Just curoius.
blkadr
I had a pressing of the Stones "Some Girls" that had a side 1 label on both sides.
I thought it may be worth a zillion dollars at the time.
I ended up selling it with a bunch of other LP's.
I guess I'll never know!

Funny. Just got a LP totally covered and sealed from a record store and guess what? It's 1976 album reprinted on 2008 that has a different artist/album side pressed on the b side. I listened to the a side of 'Legalize it' by Peter Tosh.... flipped it over and Nat King Cole 'LOVE'. I thought it so cool that I decided not to complain and keep it. :) 

BTW, wondering how much this might be worthy nowadays? :) 

Could be worth a fortune to some eccentric collector, like the famous air mail stamp from the 20s, with the upside down airplane.