Has a FIBA World Cup game ever ended 57-56?
Exactly once. On October 23, 1950, Egypt beat Spain 57-56, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 57-56 in league history.
That makes 57-56 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 58-56 has happened never and 57-57 has happened never.