At that time, dually beds were the same as fleetside beds. The only difference was at the wheelwells... Pretty much just some bolt on fender extensions.

Also, the axle is a standard width, so putting on a fleetside bed and standard single wheels (without the dually offset) will make it look like a normal pickup. That era GM truck produced a lot of fleetside 1-tons.

Oh yeah... If you convert the rear to singles, make sure you budget for a full set of 4 wheels. The fronts are offset as well (in order to facilitate tire rotation).

One more thing, unless it was modified or special order, the bed mounts will match to any bed from the same body style. This usually includes short beds on lwb frames as well as long beds on swb frames (don't ask <img src="/forums/images/graemlins/rolleyes.gif" alt="" />).