Couple 46rh questions

A light duty basic 1500 2WD could have a 42RH with 5.2 engine. They were not as common, but they are out there.
As moparmat2000 said, look at the shape of the pan. The 46RH had bigger internals, so it moves the intermediate servo out to the right side, same shape as a 727.
In the above pictures it also looks like the slimmer case, where the clutch packs are.
Nothing wrong with a 42RH for your swap either. It will require much less cutting.