he won 3 titles. but 2 of those were wbo title shots. back in those days the wbo was lightly regarded. mckenzie had come off losing the european title and got a crack at a wbo title. :yep
it's a lot more highly thought of now than back then. although even now it's still seen as the worst of the 4.
Joe Calzaghe is the Super Middleweight Champion of the World; he holds the championship with or without the WBO. Indeed without he would have a bit more money!