Has an AFL game ever ended 51-33?
It has. 51-33 has been a AFL final 3 times in 16,622 games. The first was Collingwood beat Sydney on August 21, 1915; the latest was Fitzroy beat Essendon on June 18, 1988.
That makes 51-33 the 1534th most common final score out of 6,607 that have ever occurred in AFL. One point away, 52-33 has happened never and 51-34 has happened 3 times. At one point the score disappeared for 42 years, between 1915 and 1957.