This is indeed a good and interesting representation. As has been said, all the records point to polished steel helmets. This is a topic that has puzzled me too. There would seem no evidence that cuirasses were worn yet Herbet Knotel in his watercolour in Elting's Napoleonic Uniforms of a Holland Cuirassier of 1810 shows one with a brass cuirass and helmet. Where he got this from is a mystery as far as I know? I know that Herbert has his critics but he, in my opinion, is usually reasonably accurate in his use of sources. There are however the odd anomoly and i was wondering if this was one of them?