although some games probably were made with only a two prong plug and I know some people here are obsessed with making every game as close to original as possible I would say that safety is the one thing that should come before originality. My guess is that MP did have a three prong plug but even a game that never had one can be properly grounded and utilize a three prong plug for added safety for the game components as well as to reduce the risk to your homes electrical system and reduce the risk of something terrible like a fire.