The colors are based of a tint mask texture. You might've seen some of them already in our data files. It's the .tga textures made out of shapes of red, blue, green and black.

Instead of reading the list as:
UpperBodyColor1
UpperBodyColor2
UpperBodyColor3

Think of it as:
UpperBodyColorR
UpperBodyColorG
UpperBodyColorB

Not all body parts uses all of the available channels for tinting so sometimes pants for example might be on Color1(R) or Color2(G) and sometimes on the opposite channel.

So its a bit confusing if you can't see the texture tint maps... BUT luckily for you in this case you want to change the skin color, which should always be Color3(B).

Basically whenever a body part shows skin, you can be sure that its Color3 that you want to mess with.

BONUS:
Just got this from Thomas Lund on FB:

Cant wait for you to approve me on the forums, so posting here This is the color guide that I use to get me the float values straight away:

http://prideout.net/archive/colors.php

TOP REDSHIRT: 0.79, 0.20, 0.08
PANTS GREEN: 0.32, 0.38, 0.17