The fact of the matter is that your argument has already disproven itself with other films, though. If he had to have the bodybuilder physique from T1 to mask the endoskeleton, how did his much leaner, less "Mr. Olympia" physique mask the Endo properly in T2? The fact of the matter is that the T-800 was an infiltration unit, that means that, in The Terminator universe, these things could go for years incognito. How are you going to infiltrate a place where everyone gets older, but you stay the same age without being conspicuous? I don't know, maybe I just like the biological tissue argument because half the others I've heard are so ludicrously asinine. "Arnold is the Scientist who built The Terminators! Do you remember what happened the last time Arnold was a scientist *coughs* Batman & Robin *coughs*. "Arnold is the guy who protected Sarah Connor as a little girl!" And this inspires the look of a Terminator that's 30 years younger than he is? "The Terminator is an artificial Endoskeleton beneath an organic body of muscle and skin, which ages like any other tissue." That actually makes sense.