Offered here is an impossibly rare tournament-used scorecard from the 1938 Masters Tournament. This scorecard is for Harry Cooper's 3rd round of the 1938 Masters, when he shot 71 while paired with 1935 Masters Champ Gene Sarazen. "Lighthorse" Harry Cooper finished runner-up at the 1938 Masters Tournament. 

We were able to date this scorecard both by Harry Cooper's score during the 3rd Round of the 1938 Masters, but also because 1938 was the only year that the exact hole yardages on this scorecard were used for the Masters Tournament (especially the 10th hole, which was extensively lengthened just before the 1938 tournament). We showed the scorecard to JSA, which confirmed that the hand-crossed out hole yardages were "live ink" with a steel tip pen from that era. 

Letter of Authenticity from James Spence Authentication (JSA)