The GGFG museum own a tankers helmet (Helmet, RAC) worn by an officer who, post-war, commanded the Regiment. The GGFG followed British practice and painted a red 'brush' i.e. plume, similar to that worn on the bearskin, on the side of the helmet. The Coldstream and the GGFG differ only in the side on which the plume is painted. I assume that the rest of the (Brit) Bgde of Guards as well as the CGG did the same.