Humongous was the first thing that popped into my head too, because of that movie poster, but reflecting on the film I don't recall such a scene in the movie, though my recollection could be off.
Although I don't recall black&white footage in Mad Max, I think it's a good guess with what little information we have to go on with that one.
Yeah, I don't believe there was such a mobile in the actual film, nor do I recall B&W footage in Mad Max, but you know how memory of something can get skewed over time. It may be different from how they're describing it.