Ok, let's dispel some myths. This is a simplification of course. Case hardening is a process whereby low carbon steel can be infused with carbon from an external source making a surface hardened steel. In the early days of gunmaking pretty much only 2 kinds of steel were available, low or high carbon. High carbon which was much more expensive was reserved for barrels and cylinders. The remaining parts were low carbon (wrought iron) case hardened steel. The external carbon that was used were materials such as charcoal, leather, hoofs, ground bone, salt, and potty #1 along with heat. I'm not allowed to use the proper term for that last material. I got dinged a few weeks ago for using it. Lets just say it starts with U. Apparently, this process produced an attractive mottled finish folks liked. Later, other materials were added to produce an even more attractive finish with more colors. At this point, the process was renamed color case hardening. Folks liked it even more. But, the additional materials used to make color case hardening were toxic and were eventually banned. Modern color case hardening is not hardening at all, but a chemically induced substitute for the color portion. MIM parts don't need hardening, the material used and the MIM process makes the material hard enough. Once produced the MIM part is colorized and machined.
Flash chroming is another matter altogether. It's just another finish that folks find attractive and matches stainless. For me it's six to one, half dozen to the other, I like them both on stainless guns, I prefer the fake color case hardened look on the hammers & triggers of blued guns.
Trading is alive and well on this forum. One mans junk is another mans treasure. It wouldn't surprise me at all if someone was willing to do an even-up trade with you. Assuming the parts you may have aren't damaged.