This kit is really old. That's all there is to it.
It's basically a promo modified to be a kit. So, it is simple., especially with the chassis. A lot of the kits back then had exhaust molded to the chassis. If you look carefully. you will see where the funny car option is still showing inside the frame for a seat locator.
Not only the above is a factor, but this tool is part of the 1966-1972 GTO kit lineup. This means it has bee modified heavily over the years
It is a 1967.