Has a World Cup game ever ended 7-2?
Exactly once. On June 23, 1954, Germany beat Turkey 7-2, and no World Cup game before or since has ended that way. When it happened it was a scorigami, the first 7-2 in league history.
That makes 7-2 the 26th most common final score out of 34 that have ever occurred in World Cup. One point away, 8-2 has happened never and 7-3 has happened 1 times.