Many platers will skip the copper plating on "driver" jobs. The copper is what fills all the small imperfections, grinding, sanding marks, etc. The process is like skim coating body filler before paint. The copper is soft so it can easily be sanded and buffed. Since the copper plate is thin, the plating/sanding process is done over and over until the part is perfect and then its nickel and chrome plated. This is the most labor intensive stage and expensive (copper ain't cheap!). If you want flawless chrome then this is the process. Personally, if the car is going to be driven I'd skip it as the slightest nick or scuff would just piss me off.