Has an AFL game ever ended 87-31?
Exactly once. On July 30, 1955, Carlton beat St Kilda 87-31, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 87-31 in league history.
That makes 87-31 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 88-31 has happened never and 87-32 has happened never.