I noticed in photo #4 where the cord is being plugged in, that there is a separate ground wire attached to the screw of the receptacle's cover plate. That would provide a ground ONLY if the box was grounded, which would only be the case if metal conduit or a cable with a grounding conductor was used. The original wiring in my house (1952) was non-metallic cable, without any ground, as was used in most homes at that time.