Rear Passenger Side Wheel Arch Trim (GM1791127) by Replace®. (Standard Line). PP Plastic. As moldings are the trim pieces attached to the surface of fenders which help accent body lines and even provide some protection, they should be kept in good condition. These Replace moldings are the perfect option. They duplicate OE unit in every detail as well as look and fit exactly as factory part. Plus, these great moldings are made from top-grade materials to guarantee quality, protection, and lasting use.