This one is really easy. Anyone that's a real Disney fan should remember episode 4 of season 11 of Mickeys playhouse when Donald duck, upon being invited to a tea party inside of Mickeys playhouse reveals that he gained the powers of clairvoyance after having found an old worn out leather book behind Pluto's dog house. Donald said "Upon opening the book I peered upon the seven gates of hell. I saw the death of everyone I'd ever known. Now I just... know."
So the answer is No. Donald didn't guess. He used his power of clairvoyance.
Interesting answer :) Good luck!
Hah. Luck is for people who don't know Disney trivia. But thank you! I'm looking forward to the real answer, I'm following you for the update.