I ran the question about the extra "no gun" right Endoskeleton arm by Sideshow directly with the person who handles 1:1 product. There is NO extra right arm as an option with the SS Terminator 1:1 Endoskeleton. Their product has the gun directly attached to the "bent" right arm. If there is an interchangeable right Endo arm, it is not a product that SS offers; perhaps it was an option from one of the earlier license holders before SS.