Has an AFL game ever ended 55-50?
Yes. AFL has seen a final score of 55-50 7 times. It first happened on June 9, 1917, when Fitzroy beat Sydney, and most recently on June 17, 1989, when Sydney beat Essendon.
That makes 55-50 the 191st most common final score out of 6,607 that have ever occurred in AFL. One point away, 56-50 has happened 2 times and 55-51 has happened 4 times. At one point the score disappeared for 37 years, between 1923 and 1960.