The short answer: No. No person has ever been able to prove that he or she filled out a perfect NCAA tournament "March Madness" bracket.
One of the closest people to accomplish the feat was a 17-year-old boy named Alex Hermann who predicted every game correctly until the Sweet 16 round. Then things started to unravel. Whether his near-perfect start was actually valid is an open question, according to Deadspin.
It's so hard to pick the Sweet 16 teams that Berkshire Hathaway CEO Warren Buffett has offered anyone of his employees $2 million if they can go 16-for-16.
The odds of filling out a perfect bracket are one in 9,223,372,036,854,775,808 (according to one estimation), but some believe the odds can change based off the quality of the field.
In other words: Best of luck with that.