I *think* 3/4 ton springs are the same width as the 1/2 ton springs, I think its the 1 ton springs that are wider. I could be wrong but that was always the way I understood it. I'll have to look at the sticker on my truck to know which GVWR it has. I'm sure its the 6200 tho. No sway bar on it but I have the sway bar from the 3/4 ton including the brackets on the frame. I also have the entire front suspension from the 3/4 ton truck. Even the crossmember. Rotor to rotor, control arm to control arm. It's going under the 1/2 ton at some point but it will be down the road.
However, I have the 14 bolt FF 4.10 axle also from the 3/4 ton truck and its going under the truck NOW. I need a new master cylinder since mine is bad so i'm guessing i'll have to have one for the 3/4 ton considering it will have 3/4 ton brakes and suspension.