It will not work, and it will not physically fit without some very intense body work. If you look at the gap between the bed and the cab, of any 00-04 QC, the bed sides actually wrapped around the corners of the cab. (My guess was to give the bed a longer appearance) But after the redesigned 05, the bed sides no longer wrapped around the cab corners. If you attempted to bolt on the 04 bed, the bed sides would strike the corners of the cab.
Your best options are to keep looking, consider a flat bed or build a custom bed. I ended up building a custom bed that resembles a vintage Power Wagon bed for my Dakota
Ed