They're all set according to Gman's RGB's that he provides when promos come out. The reason some of them look different is because when it's a flat color, you dont get shaded or glowing finishes like you do on the joints ingame. So, if you do textures and use the colors, they WILL match.
However, if you find an incorrect RGB, please tell me and I'll adjust it and get a new swatch file uploaded.