Standalone CCU'ed
Standalone CCU'ed is a complete ship or vehicle. It is not an upgrade! CCU'ed simply means that it was created by upgrading a smaller ship or vehicle to the one you are buying. Please also note that in the gift email, only the ship that was used as the base for upgrading will be named. Please don't worry, the actual ship you will see in your hangar will be the one you've ordered.
For example, this is how a CCU'ed Polaris looks like in hangar on RSI website.
When you unfold the details you can see that it actually contains a Polaris
Original Concept
Original Concept is a ship or vehicle that is not upgraded in any way or form and comes with Life Time Insurance (LTI). They are usually sought after by collectors. Here is an example image of Original Concept Carrack.
Some rare packages like Collectors Edition ones might be categorized as Original Concept even if they were upgraded, but that's because the main value comes from the original package that is included and not the upgrades. In those cases the upgrades will be listed in the title and exact contents shown in the screenshots of the listing.
Standalone Not CCU'ed
Standalone NOT CCU'ed ships and vehicles as the name suggests are simply items that were not upgraded. They are similar to the Original Concept ones but they do not have LTI.