Why don't you ask someone who owns a Selectric Composer
like this guy.
The Selectric Composer cost about $4000 in 1973. Adjusted for inflation, that's the equivalent of about $20,000 today. Who believes that a National Guard unit had one? Who believes that a man whose wife and son say couldn't type would use one to create simple memos, including swapping out type wheels to create the superscript? Who believes in the Easter Bunny?
You might also want to check with a leading typography expert, as referenced here.