There was a discussion on the Nihonto Message Board in 2010 discussing whether or not iron Namban menuki even exist (look up on google- NAMBAN FK / MENUKI for the thread). Good condition- gold worn or missing on some spots on both menuki and fuchi kashira. Some light rust on pair of menuki (see pictures). Menuki measure 1 7/8 inches long, 1/2 inch wide and just over 1/16 inch thick. The fuchi measures 1 1/2 inches long, 7/8 inches wide and 9/16 inches tall.
Akago ana measures 1 1/16 inch by 1/4 inch. The kashira measures 1 5/16 inches long, 11/16 inch wide and 1 7/16 inches tall. Take away 1/8 inch for inside measurements (1/16 inch thick). See my other Namban pair of menuki and other sword fittings.