I saw this earlier but couldn't respond. No reason to doubt Mr. McCormack at all, but if it is a help to some, Kevin Holland's excellent book "Nickel Plate Road Diesels" would be a second source that would verify that info. The PA's are fascinating to me.
I also want to say, MTH did a fine job on the Rail King PA's a few years back (I know, by no means a prototypical model, but hey its what I can afford). The paint, depending on the light, will give that white appearance, but it definitely has a metallic silver tint to it.