It depends on what you know already. You asked for help, but how much do you want?
In your first post you said: "Both of these kozuka are thick solid material, not plated. that's about all I can tell you about them." Then you mentioned that you knew one was copper.
So I told you the other was probably iron, but you then said: "Yeah last one is inlaid iron. Mumei."
This made me feel stupid. If you already knew that it was iron, why ask, and why not give the information that you already knew?
So now, if I add anything more, you might well say that you already knew that, so I am not really feeling generous any more.