Reference the fonts used on the suspect documents.
On the 4 May 1972 document note "2. Report 111th"
where the th is elevated.
Note, also the 18 August 1973 document "feedback from 187th" where the th is elevated.
Note, also the 01 August 1972 document " 147 th Ftr"
shows the th not elevated.
In the first two instances the computer used automatically elevated the th. In the third document the computer did not automatically raise the th because the person placed a space between the digits and the th.
Do not think any typewriters back in the '70's could automatically raise or minimize the size of the type font
behind the digits in a numerical sequence.
Recommend others check this out.
As an old printer I could not spell printer but now
I are one!
Not any that I used back then.