Keep in mind that we're talking about an Air National Guard unit
They weren't exactly high on the pecking order for getting new equipment back then (e.g. flying F-102s in 1973, which were soon afterwards converted to target drones), so the chances that they would have some high end specialty typewriters or typesetting equipment is rather slim.
For comparison, here are a couple other TANG documents from that era. Notice that they're not in proportional font and don't have superscripted letters like "th" in 147th.
Interesting.
