Yes, you need to change the wheel sets. I'm not sure what the comment above about insulated wheel sets is about. 3-rail wheel sets are not insulated...
Anyway, get you some wheel sets, and some 3-rail couplers and convert them. I do not know the design of the trucks; are they "Weaver-design" (Weaver trucks can be easily used) or not?
Or - find some 3-rail Weaver (or other) trucks and fiddle with paint colors until you are happy. I'll bet that this H'watha truck color has been produced. Weaver's Scalecoat paint line was sold to...somebody. Sounds like Internet search time!