Has an AFL game ever ended 122-56?
Exactly once. On May 28, 1955, Richmond beat St Kilda 122-56, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 122-56 in league history.
That makes 122-56 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 123-56 has happened 2 times and 122-57 has happened 2 times.