Thanks, STtNGFan. Without researching TOO deeply, I reasoned what would be the closest analog to a police box in the US of 1963. Since America did not employ police boxes by that time (though it supposedly developed them in the late 19th century), I figured the next best thing would have to be a commercial pay phone booth. But the brushed metal and glass with blue and/or red accents would look too state of the art. No, you'd want something that looked "old" in '63. Thus the all but phased out wooden boxes would "parallel" better with the equally "old" police boxes.
Tangently related, my town's regional hospital, despite being remodeled over the years retains a pair of wooden phone boxes in the main lounge area as a bit of nostalgia. Really! The pay phones were removed years ago since nearly everyone uses cells, but they still stand there with their folding doors. I think it's great idea. One can use them if they wish to keep their phone conversation a bit more private and avoid disturbing others.
Those antiquated booths kinda' gave me the idea.
Originally, I assumed those "vacu-formed/blow molded" portable toilets were invented in the 1970s or later. But the Wiki' article (which I know is NOT an infallible source of irrefutable information) states "the first US patent for a polyethylene plastic portable restroom was issued in the 1960s to George Harding, who was a co-founder of PolyJohn Corporation with Ed Cooper and George Hiskes." (It did not pinpoint an exact year, so they MIGHT have existed in late 1963.) But a phone booth is just a bit more classy.