Has an NCAA Baseball game ever ended 31-12?
Exactly once. On April 11, 2008, Missouri beat Texas 31-12, and no NCAA Baseball game before or since has ended that way. When it happened it was a scorigami, the first 31-12 in league history.
That makes 31-12 the 457th most common final score out of 531 that have ever occurred in NCAA Baseball. One point away, 32-12 has happened never and 31-13 has happened 2 times.