Has a FIBA World Cup game ever ended 86-83?
Exactly once. On September 2, 2002, Brazil beat Angola 86-83, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 86-83 in league history.
That makes 86-83 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 87-83 has happened never and 86-84 has happened 3 times.