If it has Hi-rail wheels, the product number ends with -1. If it has Scale wheels, the product number ends with -2.I would also assume that all 3 rail locomotives from MTH are delivered with Hi Rail wheelsets UNLESS specifically ordered with scale wheels.
It is Williams traditional line spec.'d for O-31. It is not the Williams brass version spec.'d for O-72.Gargraves shouldn't be a problem, but I don't know about O42, which model is this?