4 door I know, but I believe its the same part. The hole in the bottom of the one in your link to Heritage, is for a clip, that fastens it to the underside of the sill... from memory, the body that has full wheel arches fitted ie a GTI body, has one less hole in the wheel arch than the base model car, therefore its necessary to trim off one of the mounting pegs that is moulded onto the reverse side of the new wheel arch trim..
You will most likely need the little blue clips that push into the holes in the body... 5 per side iirc

Thom