Bermuda is correct that they were cranking out drums at a breakneck speed. I have seen many sets that were dated the same day but I usually have not seen the supra match the set with a date.
The sets were made seperate from the supras and when a set was completed, I'm sure they went to the pile of pre-made supras and just added one to the set at random. I don't know how far ahead the supras were built though and if they were just cranking them out, there could be a leeway with the dates. My 1969 mod orange super classic is all dated March 26th 1969 yet the supra that is origional to the set is dated March 20th. Maybe when the set you have was made, the supra pile was low and a drum made that day went with the set. I would not really think it would really increase the value too much but is as Bermuda says good knowing that all the pieces came together.
I have not seen very many if any older sets with consecutive serial numbers either. Badges were just grabbed out of a big bin so someone would have to actually look for matching numbers and with the busy schedule they were keeping, I'm sure there was hardly time for that.
I ordered a classic maple Ludwig set with B/O badges in the spring of 2012 and it was a simple four piece 22,13,16 with 5x14 snare and canister. When they set came all of the badges were in sequential order. The canister was back ordered so it is different but I never asked Ludwig to make the drums that way. That was a bit of a cool surprise.