Three basic objections:
1 The Executive was a very expensive machine, and it stretches credulity to think a National Guard would have even had it, let alone used it to type up a personal CYA memo.
2 Having proportional spacing is not the same thing as getting the exact kerning as per the supposed "memos" in question.
3 Yes, superscript characters existed at the time. One would have had to replace the font ball. So, we are asked to believe that Killian (or, rather, since Killian *didn't type*, his secretary - who didn't initial it for some reason) was typing this memo and found it SO important to have the "th" raised that he/she paused to swap font balls, make the raised "th", then swapped again.
Each one of these three objections on its own gives one reason to think it very unlikely that the memos are genuine. Multiplied together and you get a miniscule probability.
There is absolutely no reason anyone has put forth to believe that these memos are real. Meanwhile, there are numerous reasons to think them highly suspect. That's enough to pronounce them fake unless/until reasons surface to think otherwise.
There is absolutely no reason anyone has put forth to believe that these memos are real.Your assignment, should you decide to accept it, is to convince the MSM of this fact.