There is a terrific little scene at the start of the episode where Kirk asks McCoy to provide Charlie with an adult role model, and McCoy tries to get out of it by suggesting Charlie needs a strong role model like Kirk. Kirk then shoots him down, telling him that flattery will get him nowhere. The look on Kelley's face is just priceless. A really nice bit of acting between Shatner and Kelley.
If you look at the scene where Kirk is explaining why Janice didn't like Charlie slapping her on the backside, Kirk is wearing his standard uniform when he's summoned to the bridge for the Antares distress call. He tells Uhura he's on his way, and when he exits the turbolift, he's suddenly wearing his green wrap!
Speaking of the Antares, is Captain Ramart a bit of a coward? To offload Charlie onto a ship with 430 people doesn't seem very Starfleet. Or was the Antares not part of the fleet? It's hard to tell in these early episodes. I suppose you could argue Charlie's control of the Antares and its crew was total, and the only time he could warn Kirk was via a distress call when Charlie was 'out of range' or distracted.