They seem like they are in a certain order somtimes... Do they mean somthing?

No, I don't believe so. Should just be colors.

V-

NPC mech colors have their meaning though. It may not work all the time but the meaning itself is this:

Green mech: NPC mech is lower level mech than yours. (Easy to beat.)
Yellow mech: NPC mech is same level as yours. (Medium to beat.)
Black mech: NPC mech is higher level mech than yours. (Hard to beat.)

Grey mech: Basically same as Yellow mech but it mostly happens when the correct color isn't displayed, then the default color will be seen.

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Aeacus