I just got through reading a history of Spaceship Earth from Marty Sklar (Sorry, can't link to it, it's on the CM portal)....where he references the original voice in Spaceship Earth, not as Vic Perrin, but as someone named Larry Dobkins.
It's not so much being re-written as it is be told for the first time. I really think that no one knew who it is, just because no one asked. "We" the disney geeks think things are word because it has been what we have known forever, but no one ever asked where it came from or asked someone that would know the truth, Marty was there, the right question.
I know one of the biggest "disney myths" having to do with the Snow White and the Seven Dwarfs statues over at the wishing well in Disneyland. For years I thought they were gifts to Walt Disney from someone in Italy and the reason they were all the same size was cause the "person that no one knew who gave it to Walt" had them sculpeted off of soap bars that had them all the same size. Well a year ago I was on the Walk in Walt Footsteps tour and they blw that legand out of the water.....I found out that the Disney company commissioned these pieces and they were made at the Tasconi foundry in Italy by Leonida Parma, a noted Italian sculptor. Unfortunately, due to a communications error, the figures were all created at about the same size. So yeah don't believe everything you have in your head about Disney, you never know when it is wrong.