Has a FIBA World Cup game ever ended 78-50?
Exactly once. On January 18, 1959, Brazil beat Mexico 78-50, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 78-50 in league history.
That makes 78-50 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 79-50 has happened 1 times and 78-51 has happened never.