Changing bionic arm color.

[WalrusMan]

Im at mission 22 and am wondering if I can change my arm color. I have seen pictures of a yellow arm and a blue arm. Would be great to get them/

[Brother Bigot]

develop new arm types

[Akutare]

The only cosmetic color as far as I can tell is from Ground Zeroes where you can get a golden arm unlock. Otherwise the different colors are the different arm types like Stun arm, etc.