I do remember watching the finale of the International Invitational Tournament last weekend, and if memory serves correctly, the ultimate winner was from Australia, and Jim Perry mentioned something about having won prizes on the Winner's Board previously (I would presume he did during the semi-finals and likely his first game in the finals).
That taken into consideration, i believe that 1987 Winner's Board Era tournament most likely had contestants playing the Winner's Board once during the semi-finals, and another one time when he/she won his/her first game in the finals.
But i'd like to ask, we're there more than nine contestants overall in the International Invitational Tournament? The only contestants who represented the U.S. we know about are Tim Holleran and Alice Conkwright, both from the syndicated run.