The 'letterhead' could have been done by the base print shop, but the date is in exactly the same font and spacing. Weird.
Looking back through some old military documents (USAF, USAF Reserves, Army & Army Reserves), I see an interesting evolution in the fonts and date formats.
Alleged letter from W's TANG commander
List of test results from USAF basic training
Proficiency report from USAF
Student rating, Army reserves
Misc. letter, Army reserves.
The TANG letter looks like some of the documents I received in the late 70s, early 1980s. Probably done on an IBM Selectric model from that time period, which didn't have an 'th' character, as I recall.
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Looking back through some old military documents (USAF, USAF Reserves, Army & Army Reserves), I see an interesting evolution in the fonts and date formats.
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Your examples also point out that 2-digit year designations were the norm back then. It was only as we neared the change to the new century where one would use four-digit years on dates. A letter writer in the '70's (NOT "1970's") would not worry about confusing the century. Especially in a memo to himself.
Besides, word processors these days automatically type in the 4-digit year for you. Another indication that the CBS documents were written quite recently, on modern machines.