Has an Olympic Baseball game ever ended 12-8?
Exactly once. On January 1, 1996, Italy beat Australia 12-8, and no Olympic Baseball game before or since has ended that way. When it happened it was a scorigami, the first 12-8 in league history.
That makes 12-8 the 48th most common final score out of 87 that have ever occurred in Olympic Baseball. One point away, 13-8 has happened never and 12-9 has happened never.