Scott and Royster fought to a 10-round draw in 1974.
Scott entered the fight ranked No. 3 by The Ring.
Royster's record was announced as 36-13-2.
Scott floored Royster in the seventh round. Royster got up at the count of five and was allowed to continue, but the fight was stopped seconds later after he was staggered by a right.
According to the New York Times, the three official judges for the fight were Frances Moore, Tom Kaczmarek and Referee Larry Hazzard. Scott was comfortably ahead on all three scorecards at the time of the stoppage: Moore scored it 4-2, Kaczmarek had it 4-1-1 and Hazzard called it 6-0.