Within the Wabash community, this is commonly referred to as the “Tri-Color” scheme.
1950 Cooke Paint & Varnish provided the original colors, Wabash switch to DuPont colors at a later date.
Dark Gray Enamel = 802-A-194
Blue = 802-L-94
Silver Aluminum = 100-A-395
So, what is “Silver Aluminum”, well, it is not white, it’s not grey, and it’s not silver.
Many of the photos look white, even the color photos. Some photos have a metallic look, but again, not silver in the traditional sense.
I think the most convincing rendition has been the use of reefer white (dirty white) with what seems like a few drops of silver, very little silver.
Charlie