Is there a quick way to determine if I already have a skin customization?

As I am finding more skin customizations for my current character, alternate charters, and various vehicles, I'm finding it hard to keep track of what I already have and don't have. If I've already got a skin, I'd rather sell or trade it - but I haven't found an easy way to tell if I already have it. I realize I could go all the way to the nearest customization booth thing - but those are often not close. Also, since I haven't tried it yet - will the game prevent me from wasting a skin customization I already have, if I try to use it?

When you view the item on the ground or in your inventory, under the name and type of customization, a red block of text says "Already Unlocked" if you have already unlocked it before.

You can sell it, or better yet, trade or give it to a co-op partner who doesn't have it yet.

If you look at the item, it says in red text under the name: "Customization Already Unlocked".