There were proportional font typewriters in 1973 (good ole' IBM Selectric), but none that typed superscripts, no matter what the font. No question whatsoever - it's a fraud. It's been cleverly made to look "old" but it ain't. Suggests whoever at CBS "vetted" that document is younger than about 45 or so, old enough, anyway, to not remember what typewriters of the day were like and to not realize how obvious the fraud is.
Cheers,
Daiwa