Is the bed off a 2006 Dodge Ram 3500 dually the same size as a 2006 Dodge Ram 1500 swb?

No, the bed of a 2006 Dodge Ram 3500 dually is not the same size as that of a 2006 Dodge Ram 1500 short bed (SWB). The Ram 3500 typically has a longer and wider bed designed to accommodate its dual rear wheels and heavier payload capacity, while the Ram 1500 SWB has a shorter and narrower bed suited for lighter loads. The dimensions and mounting points differ, making them incompatible.