My guess is it might be a steel back proto-type Town Car which at least one was made. It has dual out side door locks, just like the Tim Kelly proto-type had. This car appears to be missing the cowl band and the cowl lamps are a question as well.
Plus, look at the '28 hood sides, and what looks like early 21" wheels and early lug nuts as well as the early style front bumper with the more drastic bends to the ends.
