All of the TIE Pilots we see in New Hope, and certainly the scanning team, are based aboard the Death Star and thus would have Death Star "assignment patches." So I feel like that actually supports my proposition?
I will acknowledge that, although I seem to recall reading an authoritative source claim that the Imperial roundel was originally meant to depict the Death Star's crew - and certainly the design seems to evoke it! - I can't find that source now. So it's very possible I'm misremembering. And even if I'm right, that's something that never got stated on screen so it was fully in the authority of the ESB team to change without causing any issue! In any case, being unable to find a source for the notion it can only be treated as my opinion now.
Just for giggles, I googled "VietNam Fighter Pilot Helmet decoration" and got some interesting results, including this:
Vietnam US Navy Fighter Pilot HelmetsThe talented INK retouch team are proud to have been part of our friend and artist Phil Toledano's new work collecting and photographing US navy fighter pilot helmets. These one of a kind helmets, from the era of the…
www.behance.net
These real-life helmets are clearly sporting whatever the heck the pilot feels like sticking on there. And this of course would have been what the art department of the time was familiar with. So I think I agree with you, that a lot of the designs ought to represent things that have nothing to do with the military, and merely represent the pilot's artistic tastes.