Has a FIBA World Cup game ever ended 91-65?
Exactly once. On September 8, 2019, Argentina beat Poland 91-65, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 91-65 in league history.
That makes 91-65 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 92-65 has happened never and 91-66 has happened 1 times.