I will admit that I missed them, but apparently they are in there. One has to assume that an explanation for them will be provided in the forthcoming prequel film, as well as an origin story for Zeus, the King of the Zombies, and how he got created in the first place. Also, how it is that he and the Zombie Queen were able to procreate, and maintain their intelligence, and bestow intelligence on other “alpha” zombies of their choosing—heck, there’s a lot that needs to be explained in the prequel. Back to those robots: They’re essentially zombie Terminators, right? The Terminators are coated with living flesh, thus they’re cyborgs, but if the flesh dies, then they’d be zombie cyborgs. But would the machines inside them still be functioning the same. One would assume so. Thus they’d still be Terminators, just Terminators covered with decaying, dead flesh instead of living, bleeding flesh capable of healing.
You know, going back to the first Terminator film, when Ah-nold lost an eye, we know that the wound had started to rot. Would this corruption have been arrested, or would the fleshly coating of the cyborg have “died” from gangrene, thus resulting in a zombie Terminator? Sadly we never got to find out. The thought of a true zombie Terminator, one walking around with pieces falling off it as it seeks to kill its target, is perfectly terrifying. Maybe if James Cameron had addressed this possibility in the last TERMINATOR flick it wouldn’t have bombed. Alas, we will never know.