Dougmo,
At first I was going to say that I had only seen e-tools with black painted blades but a little bit of looking indicated that field gray and blue gray colors were also confirmed. However these seem to have been factory applications, not done by units or individuals. Of course, the latter may have happened in units commanded by ambitious types but in the field,
there's not much better than dirt to camouflage a shovel.
FWIW
Ron V