Those old cloth ribbons had their own problems.
You could analyze the heck out of the typeface information and arrive at only one conclusion ~ two typewriters were used at different times in the production of the original document BUT they had their tabs set identically. I suspect they were made by different typewriter manufacturers but I don't know. Someone needs to hustle up their grandfather who used to repair typewriters for a living ~ see what he says.
If you've seen the article to which *I* am referring, then you have missed the salient proof contained in it. The "t" is so distinctly different in it's several iterations, that it simply cannot be argued to have come from the same typewriter. No conceivable distortion of ribbon, paper, or any other conceivable typewriter mishap can account for the distinct difference in shape between one of the "t"s and another.
I am having difficulty finding the article, if you know where it is, do you have a link?