Yeah, but those are robo-abs. It lacks the organic quality of the musculature sculpted on Rattrap which looks more 'fibrous' and 'sinewy' (for lack of gooder words). They're like the kinda abs you see on Iron Man's armour. Besides, the idea is for the robot mode to look organic while the beast mode looks robotic. OpOp looks robotic in both robot and beast modes, whereas other Transmetals look robotic in beast, organic in robot.