Has a FIBA World Cup game ever ended 80-49?
Exactly once. On July 1, 2018, Chad beat Guinea 80-49, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 80-49 in league history.
That makes 80-49 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 81-49 has happened never and 80-50 has happened never.