Odd paint color on 1918 doughboy helmet?

I have a WWI doughboy helmet painted black. It has a WWI liner made by AJ Bates Co of Webster Mass and a date of Oct 1918. It has the number 9 painted on the bottom edge of the rim like most US helmets of WWI. It has saw dust mixed into the paint and the seller claims it is either dark brown or black camouflaged. The problem is I can find no one who can verify a US army or marine group who used this color.Odd paint color on 1918 doughboy helmet?
check with military.com to see that unit used that color for a unitOdd paint color on 1918 doughboy helmet?
When dealing with militaria items, buy the item NOT the story!!!