I don't recall which number WD it was but it was when the Crusader came out I think. They have an all-black paintjob with a yellow circle enclosing a yellow "Imperial Fist," like their chapter symbol, only yellow. There may be pics in the new rhino WD too, I don't know.
I like the idea better (I can just primer the tank black instead of painting endless coats of that thin yellow paint on it), it's just a reverse color scheme if it isn't the norm- instead of yellow with black fist, black with yellow fist.