My pre pro#2 reference pics are limited but it appears the left is the same color as the shoulder and knee armor.
The right i am not sure of. It appears to me to be a brownish color.
Hopefully someone with better reference pics can chime in.
The left one is yellow, Lee suggested to use UP Armor yellow for that one. The right is reddish brown, I would probally use a mix of the red you use on the ROTJ gaunlet with a little brown mixed in.