Has a FIBA World Cup game ever ended 66-59?
Exactly once. On May 16, 1963, Peru beat Canada 66-59, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 66-59 in league history.
That makes 66-59 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 67-59 has happened 3 times and 66-60 has happened 1 times.