I came across this, and I'm not sure if you already know the answer by now. I personally am fascinated with military history! So, the things with questions were about the tail markings, and the pain jobs. And I'm pretty sure I know them both!
Tail markings, aka tail codes\base codes:
We will start with the easy one, NP. NP is the base(stationing) code of the VC-3 UNIT, like the VC-4 (the Vought F4U) which is the plane they were all modeled after. Stationed in, you guessed it, the (North) Pacific ocean! And yes that's now, on modern (military) aircrafts, changed to base code NX.
So I believe NP is their base code, and because they are a unit, you only get 1 Base code. You get your unit marking worn by usually just the leader, and you get your Individual marking, which are the numbers they have. And that brings me to my theory on JW.
Like I said there's only 1 plane that bears the unit code, so JW is NOT the unit. Also because JW base code is for the fleet logistics support squadron 62 (way bigger/heavier planes)
That leaves me with common sense of the history and lore they give us, it's quite obvious when you think about it. They are based off the real āJolly Rogersā that are in this universe named, āJolly Wrenchersā when taken in abbreviation: āJWā. Are things clicking for you guys? Then it would make sense, aside from the skull and crossbones patches they have painted on āskullā and wrenches, what other pride of their squadron can you wear? Your name of course. Which is why some will have it small, but they all have it in some way!
Red and blue, why? Well, easy! Supply, demand and most importantly, speed. In the beginning the US planes had blue coats, white stars, and to complete their flag, red stripes. And you are right that the red ones are the older ones, though not necessarily. There were two reasons to red being the older planes. At first when the planes were made, they had more time, and as the war went on the demand for new and more planes got higher and higher. Also red was used by the first manufacturer that provided the US with planes, when demand got far too much the US also got another company to make planes, that used a blue outline. So red was still manufactured alongside blue for a little while. Though! In September of 1943 red was fully surrendered and all new planes, and ones that could be afforded to repaint went blue. Which brings us to reason number two; also very importantly, because the Japanese used RED. And some US planes had friendly fire, due to the speed and distance it's hard to read the codes and numbers on a plane. So to avoid more friendly fire, they fully went to blue. As red was for Japan. So the light blue was for better visibility/identification.
Some minor things I want to air out before I hide away again:
The box/tape. It was indeed to keep leaks And loss of vision, but not just by oil, also by the humidity. Some, however, were also patches. Repairs from tears or bullet holes.
And the checkerboard rudder marking. A version of the Vought 4 was called āthe independenceā and that model had the checkerboard paint job. But I think you're right as in that they gave it to skipper, due to being his name and also recognition as a main character.
They really did try and make it to reflect our history, and respected the plane of the Vought F4U corsair. The identification of the unit and the individual In markings was well done, even with some added extra of the big JW, which would be undone as there can only be ONE base, hehe. But I can forgive it, most references of these planes still on show today have their own rudder markings. And let's not forget, it just looks cool <3
But uhm, this rant has gone on for probably way to long sooooo, hope this helped ^^ā