Has a FIBA World Cup game ever ended 91-54?
Exactly once. On August 31, 2014, Spain beat Egypt 91-54, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 91-54 in league history.
That makes 91-54 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 92-54 has happened never and 91-55 has happened 1 times.