It appears that the USGA has all the cards:
Ouimet's most significant memorabilia resides at the USGA Museum, in Far Hills, N.J., in an exhibit entitled "America's First Golf Hero." It includes his putter and four of his irons from his1 913 victory – mid-iron, mashie, mashie-niblick and jigger; the three balls used by Ouimet, Harry Vardon and Ted Ray in the playoff; their scorecards and Ouimet's championship medal. It also houses his championship medals from the 1914 and '31 U.S. Amateurs.
His red R&A jacket hangs there, as well. Funny story about that coat."My sister had one of those portraits over her mantel piece," Barbara tells, referencing the one that hangs in her house. "One day there was a girl playing there, and she said to Les (Barbara's niece, Leslie), 'Who is that?' Les said, 'That's my grampy.' The little girl says, 'What is he, awaiter?'
"Dad would have gotten a big kick out of that."