Has an AFL game ever ended 161-51?
Exactly once. On April 11, 1970, St Kilda beat Fitzroy 161-51, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 161-51 in league history.
That makes 161-51 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 162-51 has happened never and 161-52 has happened never.