The difference is the fitment of the parts.
The look a lot alike. But the 4x4 parts mount up differently because they have more Clearance.
The Door will probably be the same. But it might not have all the options that came on the 4x4 because they generally tended to be better equipped.
The bumpers are definitively different though.
Try
www.nix99.com they specialize in used Toyota Parts.