Has a FIBA World Cup game ever ended 126-71?
Exactly once. On September 7, 2019, Canada beat Jordan 126-71, and no FIBA World Cup game before or since has ended that way. When it happened it was a scorigami, the first 126-71 in league history.
That makes 126-71 the 240th most common final score out of 863 that have ever occurred in FIBA World Cup. One point away, 127-71 has happened never and 126-72 has happened never.