Has a FIBA World Cup game ever ended 89-86?
Exactly once. On July 13, 1986, Italy beat Canada 89-86, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 89-86 in league history.
That makes 89-86 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 90-86 has happened 2 times and 89-87 has happened 2 times.