I think they are referring to your statement about the JoHan body and bumpers being modified.
Johan promo kit and NASCAR racer version had the exact same bumpers and grilles castings.....showroom stock lights and details. (but for the NASCAR gas filler)
JoHan supplied covers for the grille, headlights and tail lights for the racer version.
The MPC racer kit was cloned from the JoHan so the two kits will swap bumpers, grille, glass, hoods etc.
The Model King was just a slightly modified reissue of the MPC kit.