In 35 years of serious collecting I've only found one mistake. That was Fleetwood Mac's "Tusk" where the two disks were the same pressing with different labels. I exchanged it for a good one. Now, what you have is REALLY a mistake.
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.