Right. IANAL, but the events of the show as captured on tape and broadcast over the public airwaves are a matter of public record. As Tyshaun said, you would probably have to get clearance from Fremantle to use any of the trademarked elements of Press Your Luck or any of the copyrighted elements of the actual episode (if you decided to pull a quote word for word for the script), but beyond that, I'm sure the contesti signed their rights away to any of that.
But they DIDN'T sign their rights away to having their NIL used as movie characters otherwise, so they (or their estates) would probably have to be renumerated for that usage as soon as those characters do anything outside of the scope of the broadcasted episode, and outside of Carruthers NOBODY else who was present that day is going to be referenced by anything CLOSE to their real name or likeness.
Again, though, IANAL.