I am genuinely not sure.
It's been a while since I checked the Marine class PDAs, but they have specified meshes for the various body sections (head, torso, arms, legs, accessories). I haven't checked the WY Commandos, but if they have the same setup, you could copy the bodypart mesh names to the Marines.
That would be a uAssetGUI job, because trying to recreate the files in the project would be a nightmare.