I just purchased a set of factory Mopar front and rear mud flaps for my 2012 3500 DRW. A search on here did not lead me to what I was wanting to know. The instructions from Dodge are very plain. Since my truck has the factory fender protector on it (front and rear have a plastic molding to protect the paint on the lower part rear half on both fenders) do I need to remove them before the install or do they go on over top of plastic? Thanks for the help/advise.