K30 frame question

[rs74]

Is a regular cab K30 dually frame the exact same as a single wheel regular cab dually. Possibly thinking about doing away with one of my cab and chassis frames and swapping some stuff over to a pickup frame. I would need to get the wider rear axle. I just want a K30 dually pickup. Been lookin at http://www.car-part.com/ for a frame since I can't find any locally. They don't list whether it is a dual or single wheel frame though.