Has an AFL game ever ended 120-13?
Exactly once. On August 25, 1906, Fitzroy beat Melbourne 120-13, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 120-13 in league history.
That makes 120-13 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 121-13 has happened never and 120-14 has happened never.