Has a FIBA World Cup game ever ended 91-79?
Exactly once. On October 10, 1978, Canada beat Australia 91-79, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 91-79 in league history.
That makes 91-79 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 92-79 has happened 5 times and 91-80 has happened 2 times.