But, Khan (and later Scotty) were both studying schematics for the Constitution class. It could just be coincidence.
Yes, the infamous MK IX/01 long range primary phaser schematic of a "starship" of a "Constitution Class".
Khan told Lt. McGivers that he had been studying "manuals" (i.e. more than one) of Federation starships. Apparently and to grasp the technological evolution that lead to the 17th starship design he also studied previous manuals and one did feature an older "Constitution Class".
Scotty studied the same schematic in "The Trouble With Tribbles" as part of a technical journal (and not the Enterprise's
manual!), but did not participate in any social rec room activities.
If he's looking at the primary phaser of the Enterprise
then I have to wonder why?
Because it's like a teenager staring at a centerfold, while the real thing is down in the basement waiting to be examined!
But that's the essential fact: The whole assumption that the TOS Enterprise
is a starship of the Constitution Class is based on a screen excerpt and a phaser schematic (indiscernible to read in the TOS footage) with no evidence that this phaser actually belongs to the Enterprise
While every ship of the Constitution Class is obviously a starship, not every starship is automatically one that belongs to the Constitution Class.
@ Nob Akimoto
in "The Doomsday Machine" could just have been named and numbered to honor the achievements of a previous starship with that name and number, not too dissimilar what happened to the starship that became the Enterprise-A