OK, Ship Customization seems to be very specifically limited in a few ways:

• Ships are made from 4 parts: fuselage, engine, wings, and “reactor core” which is basically a module that sets the Class S,A,B,C.
• You can’t edit an existing ship, not even just the color, as far as I can tell; if you want "what I have but in green" you have to collect the salvage parts to clone it, then you can tweak the color.
• If you salvage your current ship, you can get X million units or whatever like you used to, OR you now have the option to reclaim a part…but you can only claim ONE of the 4 part categories.
• REMINDER: you can package up all your ship modifications and store them in your exosuit/freighter along with anything in ship storage...if you have the space. Salvaging a ship to get those cool wings in your inventory without emptying it first is gonna make somebody really mad this week, I guarantee it.
• I already found an S class Reactor Core for sale from the Explorer’s Guild (which I could only buy because my standing is super high)…so If I scrap this here long nosed fighter and salvage the fuselage, I would still have to go grab the other 2 parts “in the wild.”
• Oh, and: fighters, explorers, haulers only; no customizing your Solar, Exotic, or special expedition Speeder. Rats. Was hoping to fix their color schemes.

Still better than the nothing we used to have, but if you wanted to just nip on by and remove that puke green accent color on your otherwise perfect ship: I don't see a way to do that.