WWI German Wound Badges

I just got back from a vacation road trip which included stops at a few antique malls. In one of the malls there was a black WWI German army wound badge. The black finish had been worn off of the high parts of the design exposing the brass metal that the badge was stamped from. The vender described the badge as “early WWI”. I am not sure what the vender meant by early; early issue of WWI or just a pre-nazi issue? In any event it reminded me of an observation that I have been making for decades that no one else seems to mention. The army and navy wound badges were first issued in March and June of 1918. At that time Germany was “on the ropes” and was suffering from serious shortages of food and metal resources. Therefore the wound badges issued during the first world war were all made of iron. Brass badges were privately made after the war ended to replace the original rusting iron badges. In my opinion a nice condition iron wound badge is much more scarce and valuable than the brass version. If the finish is not worn off on the high points of the badge use a magnet to separate the iron from the brass versions.