Has a FIBA World Cup game ever ended 51-40?
Exactly once. On November 2, 1950, Chile beat Brazil 51-40, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 51-40 in league history.
That makes 51-40 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 52-40 has happened never and 51-41 has happened never.