Has a FIBA World Cup game ever ended 91-83?
Exactly once. On September 4, 2014, Angola beat Australia 91-83, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 91-83 in league history.
That makes 91-83 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 92-83 has happened never and 91-84 has happened 2 times.