Has a FIBA World Cup game ever ended 58-49?
Exactly once. On June 28, 2018, Uruguay beat Paraguay 58-49, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 58-49 in league history.
That makes 58-49 the 475th most common final score out of 1,178 that have ever occurred in FIBA World Cup. One point away, 59-49 has happened never and 58-50 has happened never.