Has an AFL game ever ended 120-90?
Exactly once. On March 25, 2017, Melbourne beat St Kilda 120-90, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 120-90 in league history.
That makes 120-90 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 121-90 has happened 3 times and 120-91 has happened 1 times.