If you have a very close look at the parts where they fairly rapidly zoom into the document (and then pause it) what you are referring to as "writor" is actually an instance where the lower case letter "e" suffers from the missing cross-bar --- which was a distinct fault of a lot of typewriters of the day. It can also be attributed to a "weak" left hand pinky finger key stroke.
I also happened to notice places where the lower case "a" is lifted higher than the common line, and the lower case "s" drops below the line.
This happens from differing degrees of impact strength caused by the typist or an odd positioning of the original key bar.
All of these instances are directly related to mechanical typewriters.
If you study the text more closely, you may find other such mechanical anomalies.
In my opinion - no one from the present day would have even THOUGHT to produce offset letter chararcters in this way.
Spelling issues - I didn't look for any.
But this to me is clearly a mechanical typewriten document.
Now, as for the validity of it - I'll let you dawgs fight that one out.
The Book of Manhttp://vimeo.com/album/2701770