Has an AFL game ever ended 81-79?
Yes. AFL has seen a final score of 81-79 5 times. It first happened on August 25, 1934, when Hawthorn beat Essendon, and most recently on May 25, 2017, when Geelong beat Port Adelaide.
That makes 81-79 the 589th most common final score out of 6,607 that have ever occurred in AFL. One point away, 82-79 has happened 6 times and 81-80 has happened 6 times. At one point the score disappeared for 44 years, between 1970 and 2014.