I built this one as a fictional Mk IVa, weekend racer. It would have been a cheaper version with a less powerful motor that someone would have trailered to a club or local road race on weekends.
The main visual difference is that the tail lights stick out further and have a chrome rim around them. The tape on the head lights is to protect the clear covers from flying rocks and stuff on the amateur tracks. If you notice; the wheels on one side are totally grey and on the other, they are grey and silver....we used to use methods like that to keep the left and right separate; to aid in chassis or air pressure set up.