The frames of the Nitro Specials were forged, milled steel, not maleable iron. You can tell the difference easily by removing buttstock or floor plate and seeing if interior of frame is as cast (maleable)or machined (forged, milled steet.) Also, the WA guns have a slightly different design of top lever and stamped trigger guards. Those were the major shortcuts in manufacture. Another was to tell is by serial #. Chopperlump