Going by every Universal complete series rerelease I can remember, they all get new pressings where the double sided discs are changed to single sided discs.
Columbo, Law and Order, The Munsters, A-Team, even Shout's rerelease of Leave it to Beaver. All had the dreaded flippers converted to...
Going by Amazon disc counts, the complete series box is 63 discs, the original sets were 54 discs total.
So, do the math. The 3 disc flipper sets become 6 disc single sided sets, and that accounts for the other nine discs to make the complete set 63 discs.
/that's assuming the Amazon listings...