The earliest Tigers had two frames welded to the hull rear wall. There were various bolt holes in these frames, allowing mudguards and tail-lights to be attached to the vehicle. This photo shows the right-hand frame on the Rye Field Tiger kit.
Here is the corresponding part on a real Tunisian Tiger. The shape is different at the place indicated.
The left-hand frame on the model has the same problem, but it is hidden by the tail-light.