Has a FIBA World Cup game ever ended 81-70?
Exactly once. On August 19, 2006, Germany beat Japan 81-70, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 81-70 in league history.
That makes 81-70 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 82-70 has happened 3 times and 81-71 has happened 1 times.