Some work was done to the shell and the roof.
Front received its windows and the roof the inlet grill for radiators
Additionally the exhausts outlets were mounted
The rear got its modified door windows, rear light and horns
The underbody received basic details (air & fuel tanks, battery boxes) which are visible in the side view
One may notice that the window & doors scheme is not symmetrical (front door and smaller window close to the passenger's compartment only on engineer's side). This is modeled after the original floor plan - obviously the brass model wasn't done with that plan on hand (it has symmetrical door & window scheme on both sides).