I've gotten around to thinking: if NBC didn't wipe over the pre-1985 episodes of the Jim Perry version of Sale of the Century, then maybe Reg Grundy Productions (which produced the 1983-89 series) itself did so, reusing these tapes over and over to record the newer episodes with each passing year, which is likely why only the last 130 or so episodes of the daytime run exist along with the entirety of the 1985-86 syndicated run. (Previously, Jason Cranmer as of 2018 had contacted FremantleMedia about the status of the daytime run, and an exec said to him then that of the 883 or so episodes presently in their vaults, none among them were before 1985, which, again, might really mean that RGP likely had recycled the tapes over and over, regarding the missing episodes.) This theory may be plausible because another daytime version of another popular game show, Wheel of Fortune, had its tapes recycled over and over again, year after year, until 1985 (again not NBC policy, but Merv Griffin's own). ~Ben
