Hory shet!
Nice find in that ad
and your original purchase. It looks identical to the advertisement and not messed with much, if any. Seat is gone of course but it wouldn't be too much effort to have an upholstery shop fab you up a pleated vinyl seat/seat cushion. The original seat was a slip-on affair [best I can tell] with a pocket on the seat back that simply slipped over the back rest.
A quick jaunt around the web showed much more documentation of the more primitive [see below] David Bradley karts [the sidewalk variety, looks like] and not much on your particular model.
I like how the pedals straddle the frame tubes and solve the problem of keeping the pedals in place with little wobble. Question though, does a child rider put his legs through the steering wheel hoop while an adult/teen rider puts his legs around the hoop and feet back into the frame? Even at this early era, it was still a man's sport as this Racer Kart and two-engine option evidences.
These karts scream 1950's era "Jet Age" if only from the "jet fighter" U-shape steering wheels.
Power Products (and Lauson) engines were purchased by Tecumseh around 1956. Is your engine 2 or 4-stroke?