Has an Olympic Baseball game ever ended 20-6?
Exactly once. On January 1, 1996, Cuba beat Italy 20-6, and no Olympic Baseball game before or since has ended that way. When it happened it was a scorigami, the first 20-6 in league history.
That makes 20-6 the 48th most common final score out of 87 that have ever occurred in Olympic Baseball. One point away, 21-6 has happened never and 20-7 has happened never.