Greg,
I think the whole smoke box was painted the same gray, but the barrel got dirtier a whole bunch faster so the result was the front tended to look brighter because it stayed cleaner longer. The linked shot of 487 in 1961 shows an engine recently out of the shop and the barrel still looks gray.
487 with fresh paint
I agree I like the effect of the lighter front.
I'm guessing the cylinder covers and running boards were painted silver or aluminum.
But like the backward flying Rio Grande, at one time or another the paint shop probably did whatever was easiest.
JBWX
Edited 2 time(s). Last edit at 11/24/2014 10:02AM by John West.