Has a FIBA World Cup game ever ended 70-51?
Exactly once. On July 2, 2018, Venezuela beat Chile 70-51, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 70-51 in league history.
That makes 70-51 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 71-51 has happened never and 70-52 has happened never.