www.autocolorlibrary.com This has most color info from 1900 to modern. I tried to find it for you but did not see that # listed. Is there any original color left on truck? If so what is it, and is it a metallic? it may be a hold over color, or a new color they were trying out and using the next year. I was a painter back in those days but do not recall wb being after a paint code on GM. It was used on Fords in about 1974 to indicate water born paint used on some trim such as hubcaps. Gm was still using Lacquer back then. It may have been a special order. As I recall most codes that were close to this were white. There idiotic about white, some years they had as many as 11 different shades of white. By doing a google search for auto color library you can find different sites that can help. good luck