Has an AFL game ever ended 171-120?
Exactly once. On April 14, 1985, Fitzroy beat Sydney 171-120, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 171-120 in league history.
That makes 171-120 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 172-120 has happened never and 171-121 has happened never.