Flickr user DrHaggis has unearthed a Mad article from 1982 that makes predictions for the saga. There are several coincidences with the actual prequels – Episode II as Send in the Clones, a Skywalker being fathered by the force, Yoda defending Kashyyyk, Darth Vader as the father of Threepio, and Artoo knowing the full story of how the Jedi were disbanded (and “holding the entire history of the Galaxy in his memory banks,” which I believe is pretty damn close to the Georgefax.)
And yet, not a single attempt at Return of the Jedi…