Has a College Football game ever ended 76-3?
Exactly once. On September 5, 2015, Ole Miss beat UT Martin 76-3, and no College Football game before or since has ended that way. When it happened it was a scorigami, the first 76-3 in league history.
That makes 76-3 the 1819th most common final score out of 2,215 that have ever occurred in College Football. One point away, 77-3 has happened 6 times and 76-4 has happened 1 times.