Keep in mind that this is just a hypothesis. If Reeves Entertainment was stupid enough to give the original tapes of all the episodes to MCA TV back in the 1980s to make syndication edits (which are several generations down from the original), and neither Reeves nor their successors-in-interest got them back, and Universal never made backups of the original network versions you might have a problem. But I doubt that's what happened. CBS received four copies of each episode when they aired them for the East Coast and West Coast feeds (one main and one backup for each), and no archivist worth his salt would store all elements of anything in the same location.
Worst case scenario they can just get the 3/4" copyright deposit tapes from the Library of Congress.
As far as I know Universal had nothing to do with the releases put out by VEI. I remember speaking to someone at Fremantle about their copies when it came out, and he said something along those things.