:facepalm:
GM doesn't....but arrowcraft, and a few other dually conversion places sell the fiberglass short bed dually bedsides. Simply take a short bed, attached the shortbed dually bedsides(or fenders depending on year) the way you would any other bedside, and Bam, you have a shortbed dually. They come with the fuel door already moved into the bedside in the proper place, etc.
What kind of work? If it was into making it a shortbed phantom dually, they wasted their time, the pair of short dually fenders are $500.
I recall seeing pics of it on here before, when it was multicolored during the build stage IIRC.