Has a FIBA World Cup game ever ended 81-54?
Exactly once. On June 30, 2022, Panama beat Paraguay 81-54, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 81-54 in league history.
That makes 81-54 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 82-54 has happened 2 times and 81-55 has happened 2 times.