from link...
The IBM Executive typewriter I found at a garage sale was magnificent, and (having been long since replaced by the Selectric), dirt cheap. Only somebody with a PhD in secretarial skills could operate it. It was a proportional spacing machine: an 'm' was five spaces wide, an 'i' was two. There were two separate space bars (two and three spaces respectively). To correct a mistake, you had to know the width of all the characters involved so that you could backspace the appropriate amount (backspace was the only single-space key on the machine). There was an arcane procedure for producing justified type which involved typing a page a first time (while using a special guide to measure where the lines ended), noting the extra spaces that needed to be added, marking the copy to show where two-width spaces would be replaced with three-width spaces (or, in the worst case, two two-width spaces), and typing the page a second time.
Do you really believe that anyone went to this bizarre extent on a memorandum in 1972? I sure don't. It beggers belief.
Occam's Razor says this is a forgery, and the forger didn't account for the proportional spacing promblem between a 1972 memo and one forged on a PC in 2004.
What really beggars belief is that a memo with a subject of "CYA" would be missed until now.
And from a conveniently dead person.
Remember the forged flyer supposedly from the Swiftees and even more supposedly picked up at RNC headquarters?