Has an Olympic Basketball (Men) game ever ended 66-55?
Exactly once. On July 27, 1952, Egypt beat Cuba 66-55, and no Olympic Basketball (Men) game before or since has ended that way. When it happened it was a scorigami, the first 66-55 in league history.
That makes 66-55 the 126th most common final score out of 698 that have ever occurred in Olympic Basketball (Men). One point away, 67-55 has happened never and 66-56 has happened 1 times.