Has an AFL game ever ended 122-50?
Exactly once. On August 21, 1971, St Kilda beat Sydney 122-50, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 122-50 in league history.
That makes 122-50 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 123-50 has happened never and 122-51 has happened 4 times.