Has an International Rugby game ever ended 47-17?
Exactly once. On February 14, 2015, England beat Italy 47-17, and no International Rugby game before or since has ended that way. When it happened it was a scorigami, the first 47-17 in league history.
That makes 47-17 the 510th most common final score out of 844 that have ever occurred in International Rugby. One point away, 48-17 has happened 1 times and 47-18 has happened never.