"Examine carefully the “fr” in the word “from” in the 18-August-1973 memo. The “r” is tucked under the “f” in the same way a Microsoft font does it. In 1972, technology available in the office, including proportional typewriters, could not do this.
No offense to Dr. Newcomer, but he's wrong here. Monospaced typewriters could produce characters with negative A and C widths, and many typewriter fonts did in fact include characters with such widths. The most common example is the underline, but on many typewriters the "M" and "W" also qualify. Additionally, some specialty fonts like the "italic" and "script" balls for the Selectric, are designed with characters that overhang following characters (in the case of italic) or intersect them (in the case of script).
There is no reason to believe that negative A and C widths, which can be produced with a monospacing typewriter, could not likewise be produced with a proportionally-spacing one.
BTW, I've seen also seen metal type with negative A and C widths. I'm not sure how it was made, but it looked like metal letters were fastened to a squared-off metal block. I don't think such type would work in a Linotype, and would be a bother even to hand set (the spots where the metal type extends past the end of a block would be rather delicate; if two adjoining characters would intersect each other, a typesetter would have to put a spacer between them or risk damaging the type.
What do you want to bet that any typewriter fonts exactly match the spacing of TrueType?
To be more specific, the author may have overgeneralized on one point, but I think he's correct the TrueType spacing is unique and propriatary. It's the simplist explanation for the failure of all attempts to duplicate the memos by means other then TrueType fonts.
Now that some has explained the kerning issue, I'm going to try matching the memos with Wordpad. I'm not as proficient with photoshop as some, so it will take a while.