The Sewell, Malnati, and Rudy Jr. are the stories I've heard as well... Doesn't mean it's true though. It may just be a well told mythical tale that's been passed on over and over again, right?
But I can confirm that's the story we hear in Chicago! (The plug for the Chicago Pizza Tour at the end leads me to believe that the writer got the story from the same source I did... eating on the tour.)