Has a FIBA World Cup game ever ended 99-61?
Exactly once. On November 24, 2017, Lithuania beat Kosovo 99-61, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 99-61 in league history.
That makes 99-61 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 100-61 has happened never and 99-62 has happened 2 times.