Armand, I don't think anyone would disagree that unpainted galvanized
does not mean "silver" or "aluminum" colored paint. I don't know of any
XM box cars that had such painted roofs, although there probably were
some. RB/RS/RP's of course are a different story... Recently vendors
have tried to mimic 'overspray' with varying degrees of success. Only
Athearn has done the dark seam caps + galvanized roof, and then only
on one model, too modern for this list.
The original cars were used extensively for PR purposes for the general public,but mainly for potential customers and may have had painted roofs.I have taken pictures from above and the paint did not fully cover the roof and appeared to be applied in an irregular pattern suggesting over-spray.I stand by my original statement that the roofs were not pained silver either ,but were unpainted. galvanize.I defer to Steve Mumley for additional comments.Armand Premo