Has an AFL game ever ended 40-29?
Exactly once. On July 14, 1900, Melbourne beat Geelong 40-29, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 40-29 in league history.
That makes 40-29 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 41-29 has happened never and 40-30 has happened 2 times.