The WM Challengers had a significantly different front, with a steel "rock knocker" pilot, air reservoirs and radiators up there. And the tender was more of an eastern type. I modified an old Rivarossi Challenger for the WMRHS, fixing some of these discrepancies. Note, I didn't mess with the steam or sand domes, I was going for a reasonably close appearance with a reasonable amount of work...

Not exactly museum quality, but certainly looked less UP when I was done with it.
A better look, perhaps...


Here's a broad side, which also shows the etched brass All Weather Cab sides that Chris333 did for the project. The tender was actually stock ConCor/Rivarossi, and is (I believe) the same one they used on their Nickel Plate Berkshire. It looked close enough to me to keep as is, although their paint was a little thick on the lettering.

The more or less finished project.
I suppose if you did away with the UP tender and applied a reasonable amount of paint, you could call it satisfactory, but without that plow pilot, it wouldn't look right to me.
Lee