Correct.
All 6 were prior to the award being voted on. Prior to 1982, the Vezina was awarded to the starting goalie of the team with the lowest GAA.
It was a team award handed to the starting goalie. For a time, it was handed to both goalies, oddly enough, thanks to the leafs. In 1965, Sawchuk won the award despite having the 4th best save percentage and 5th best GAA. The Leafs has the best GAA… because Johnny Bower led the league in both save percentage and GAA. Since Sawchuk played 36 games and Bower played 34, Sawchuk was considered the starting goalie and took the award. Sawchuk demanded that he share the award with Bower, and it became a shared award until it became a legitimate voted award in 1982.
There were times when the Leaf goalie may have won the Vezina had it been voted. Turk Broda in 1941 and 1948. Harry Lumley in 1954 and 1955. Johnny Bower in 1961.