As this is not a localization issue, I am unable to say whether or not it is a bug at all, and if so, if the issue is with the graphics or the recipe materials needed. I have confirmed, however, that the recipe for iron gauntlets calls for bronze chain sleeves, meaning the color is most likely correct. It is the iron sabatons, however, which require iron chain, and so I have forwarded your concerns in a bug report to the development team member in charge of items.

Thanks for the heads up, and nice eyes of the hawk there, BraveStarr.