I don't recall the IBM Selectric using Times New Roman font.
It's been awhile since I've typed on one, but I recall that you could get different balls -- a serif ball (which was more like a Courier font), a sans serif ball, and a script ball. By the 1980s you could get special balls, like one with an enlarged "speech" font. (I just realized that that's more balls than you can find at CBS.) ;)
Typewriters didn't auto-center until they came out with those with some "memory."
You are correct. I think there were only 10 pitch pica and 12 pitch elite (may be reversed). We still have some of the later IBM Selectrics here, and they do not have Times New Roman font. None had auto center or superscript. I remember re-typing many memos because the headings were not centered.
I used a memory typewriter in the late 70's. I don't know how much earlier they were out than that. But I kind of doubt that the military had state-of-the-art office equipment.