The photocopy angle of this story is interesting too. In the early 70's photocopies were not as available as they are now. I remember taking typing class in 1973 and learning how to use carbon paper. If Killian really typed these memos, he would have kept the originals---not a 15th generation photocopy.
It would be easy to test the originals. The letters on all documents printed on todays lazer printers can be scratched off with a knife.
A document in 1972 would have been created with real ink.