No, just left overhang and right overhang. Consider the following examples in "Courier New" [a font everyone would agree is not kerned]
IMMI mwThe top example on the left appears narrower than the second, even though both contain the same letters and there's no kerning. Further, if you look at the examples on the right you will notice that there is overhang between the letters shown even though, again, "Courier New" is not kerned.
By the way, many typewriters did have characters which extended far enough left and right to overlap adjoining characters if typed in the right sequence. Kerning is not the issue. Overhang is not the issue. What is the issue is that the document matches Word's default behaviors so perfectly.
So the blogger is making a valid point even if she has asymetrical positioning of the letters confused with kerning. It rules out all the other kinds of type writers outside of the Composer I suppose.
In order for the type to overlap, the center to center spacings between type blocks must be less than 1/2 the width of the two blocks. First this requires proportional spacing, and second, unless your typewriter has memory the designer cannot allow this, because you must have kerning or you cannot guarantee that you will not get overlap of typed characters (i.e. you must have knowledge of kerned pairs).