Ramblings -
In case anyone else notices that the smokebox front on the Lionel (and MTH, too) scale Challengers just "doesn't look right", as I did, well, you're not wrong - they aren't modeled correctly. (The brass Williams 4-6-6-4's front is correct.) This is my Lionel Clinchfield unit.
So - I bought this smokebox front from Stevenson Preservation Lines - I'm not sure of the original tooling source - Lobaugh? - but I intend to replace the Lionel front with this. I'll add handrails, a number plate and some more-scale-sized class lights - they (and the number boards) won't be lit, which is fine by me.