Has a FIBA World Cup game ever ended 76-55?
Exactly once. On September 2, 2010, Australia beat Angola 76-55, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 76-55 in league history.
That makes 76-55 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 77-55 has happened never and 76-56 has happened never.