the car vs truck wgt difference is minimal or nothing, depending on year of truck and dia. of tubes. Still really nothing.
the big issue with the dodge housing is the solid spring perches (rot under perch) and the encapsulating lower clamp that causes corrosion(from debris between it and axle tube).
If the axle is to be narrowed, unless it is for something a bit less than abody width, the rotted section of tube is in proxcimity of the joint.
That being said, a rot free tube is has no issue.
someone with proper tooling, welding equip and skills, $200-$250 is fair imo.
someone doing it for $50 is either a favor or very hungry, would question someone giving me a quote that low.