Yeah, threshold scores for most of the games were the score from the previous year's tournaments. For a few of the games which were "new" games for the 1986 tournament, it looks like the picked an arbitrary score (e.g. there's no way 500K on 1942 was really the high score).
My understanding of the "back story" on the tournament was that it was supposed to help prevent bogus scores that had popped up on the TG scoreboard and in the magazines by limiting score attempts to a smaller number of "trusted arcades" and very clearly spelling out the required settings and any special rules.
-George