I worked on that show for the Chiodo Bros. back in 1990 or 91. It was, in fact, a big mix and match session, for the most part. Killer Klowns from outer Space heads with appliances added on. I think there were a few 'original' heads though... and arms/hands, like for the lead, "Tranitor" or whatever his name was. Bart Mixon was the supervisor/coordinator, I remember Andy Clement as one of the sculptors, and lots of other 'local' artists of the day there too. I was a moldmaker, fabricator and finisher. We also did Land of the Lost (the 'new' TV series) and Critters 3 and 4 there, at about the same time...
I have a few assorted pics from the show, including one big group shot of most of the trolls together. I'll see if I can dig them up. I'd assume that the Chiodos still have alot of the troll parts, though maybe cannibalized by now?