Has a FIBA World Cup game ever ended 58-56?
Exactly once. On February 23, 2018, Romania beat Croatia 58-56, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 58-56 in league history.
That makes 58-56 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 59-56 has happened never and 58-57 has happened 1 times.