$120 bucks for all 4 bearings and seals is not expensive.
Most 6 lug brake kits are set up for 12 inch disc. Most 5 lug brake kits are set up for 11 inch disc. If you are using a 5 lug bolt on bracket for the 6 lug brakes, you will likely have to turn down 12 inch 4wd rotors to 11 inches, or find a rotor that will work.
On the 6 lug brakes, the rotor does not slip over the studs. The rotor sits on the rear side of the hub, and new studs are pressed through the rotor and then the hub to form a rotor/ hub assembly.
Of course this might be all moot if you are designing your own set of brakes. But hey, if you like a challenge go for it. TX is pretty far from CA, so I feel safe.
Here's a link to a tech article with pictures.
http://www.classictrucks.com/tech/0902clt_1955_1959_chevy_truck_cpp_six_lug_brake_kit/viewall.html
