I've been looking at those .pdfs some more. I'm no document expert, but I'd stake money on them not being done in the 70s. Like to guess why? They're done in proportional fonts!
Bear with me here. A proportional font is one in which the letter "o" takes up more horizontal space than the letter "i". With the coming of computerized typesetting, we've all become so used to seeing it that we take it for granted.
But old-fashioned typewriters can't do proportional fonts. Modern ones can (yes, Virginia, they still make typewriters) but the old ones couldn't--not even the vaunted IBM Selectric of that era could handle proportional fonts. Until sometime in the 90s, all typewriters used monospaced fonts--one where every letter took up the same amount of horizontal space.
So if I'm right on this, then someone is hoaxing. The question becomes who and why? This is going to get interesting, and the November election could wind up turning on the answers.