Yup - I was asking more about the use of the specific term "gee" in dialogue, but the fact that Kirk's ship regularly suffered reduced gravity is of interest as well.
I wonder if we're really supposed to be thinking our heroes are under the influence of 0.8 Earth gravities? It could be that the "gravity is down" situation only prevails on some other parts of the ship.
Constant low gravity is always difficult to fake convincingly. I recently watched "Moon", the 2009 flick about the lone helium miner, and that was pretty elegant. The hero moved fairly Earth-normally, out of supposed long experience, but was shown effortlessly lifting great weights and on occasion jumping with a bit more spring to his step than one would expect. Moondust flew in great arcs unhindered by air resistance. Nice and smooth - but Moon gravity really shouldn't allow for normal walking, no matter how careful you are.
Point eight gees might, though.