The TOS Recreation Room(s) Sets

The evolving nature of the crew quarters adds (IMO) to the feeling of time passing and the crew getting settled in.

Armed to the teeth? Maybe not. But the show evokes a "submarine mentality" more than once; there is a near total absence of windows in the recreation rooms, the crew quarters and public spaces. When characters do gaze out at the stars (which only happens twice that we see) it is established as an unusual event. The portrayal of shipboard life then is one confined within the bulkheads and the crew have little interest in stargazing - it's just a place to work, as far as they are concerned.

The Enterprise as initially designed did not have windows, at least not in the number that the final model possessed. It was Roddenberry that insisted upon them (and Jefferies dutifully added). So even from the beginning there were two differing design/aesthetic outlooks; MJ disliked windows because they were unneccessary and were points of structural weakness in a real life vessel, GR liked them because they provided a sense of scale and made the ship look pretty.

In any case, we are left with these lit up circles and rectangles on the side of our ship. Interpreting most of them as sensor pallettes is not too much of a stretch, I think (YMMV)