Has a FIBA World Cup game ever ended 76-50?
Exactly once. On August 9, 2017, Estonia beat Kosovo 76-50, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 76-50 in league history.
That makes 76-50 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 77-50 has happened never and 76-51 has happened never.