Not exactly. From 1950-1987, the CWS was a true 8-team double-elimination tournament.
Starting in 1988, the CWS format was changed to two 4-team double-elimination tournaments (brackets), with each tournament/bracket winner playing in a 1-game winner-take-all event. This change was made so that CBS could broadcast the championship game live at a specific date/time. To the best of my knowledge, 2002 was the last year CBS broadcast any CWS games.
This means that the "1 game instead of 3" did not apply during the 1975 CWS, nor to any of our pre-1988 visits to Omaha (1975, 1977, 1981, 1982, & 1985).
Pre-1988, when there were three teams left standing. they held a coin toss to determine who played first.