RealTruck carries a great selection of custom door sills your 1991 GMC C/K Pickup 3500 truck. Find a wide selection of door sills you need to upgrade your GMC pickup. RealTruck carries stainless steel, billet aluminum, diamond plate, and illuminated door sills for your 1991 GMC C/K Pickup 3500. We also offer free, fast shipping, and the best customer service you can find. Shop now or give us a call at 877-216-5446.