I have several 13mm and 18mm full diamond paks of engines including several of all flavors of B14's !
All have engine dates 1974 or earlier, but that does not mean they did not still exist in 1975.
I know the last year that D13's existed they were available individually or in 3's and were shipped in tubes. That was 1971.
In 1972, the D12 came out and so did Solar Igniters.
1971 was the last year one was able to order single engines, as that was the last year of shipment tubes.
I do not know for sure if Estes ever had 24mm Diamond Paks. I have seen a LOT of rocket engine packaging and rocketry stuff over the past ~35 years in the hobby and can say I have never seen Estes D engines in diamond packaging. That does not mean they do not exist though. I do know I have a pak of D12-5's with a 1976 date on the motors and they are in a pink blister pak.
Possibly Rocket Doctor or JumpJet may know the answer to the 24mm diamond packaging question.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !