Has a FIBA World Cup game ever ended 65-50?
Exactly once. On September 14, 2018, Tunisia beat Morocco 65-50, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 65-50 in league history.
That makes 65-50 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 66-50 has happened never and 65-51 has happened 1 times.