Also not noticed by me until late in life was the fact that Shatner crunched his communicator when he rolled over it when they popped in. The grille is bent and stuck open in a few shots after he gets up. Also, Shatner has no heels on his boots in the fight scenes.
That rollover accident has been on my radar for like 15 years now. It's frustrating that they don't seem to make any mention of it on the site that tracks everything about TOS communicators:
http://www.herocomm.com/Home.htm
Kirk's flat-soled boots can also be seen in "Plato's Stepchildren"
http://tos.trekcore.com/hd/albums/3x10hd/platosstepchildrenhd0630.jpg
They're a great improvement over the lace-up boxer's shoes he wore in "Arena" and "Tomorrow is Yesterday" for the big brawl. A similar thing was done on Wonder Woman. Lynda Carter's red boots had tall spike heels, but a flat-soled pair was used for scenes with running.