Dull would be right - these plates were made of cast iron, steel or white metal, never brass (except on the 800 class). Not only that, but the rims were painted cream, which would not have shone, or in some cases just rubbed down to bare metal (rim and numerals) with standard grey background. Thus, the duller it looks, the more accurate.
Given the brassy finish of these plates, in fact some dumbing down of the shininess is appropriate.