Has a World Baseball Classic game ever ended 7-4?
Exactly once. On March 16, 2009, Cuba beat Mexico 7-4, and no World Baseball Classic game before or since has ended that way. When it happened it was a scorigami, the first 7-4 in league history.
That makes 7-4 the 47th most common final score out of 80 that have ever occurred in World Baseball Classic. One point away, 8-4 has happened never and 7-5 has happened 2 times.