I recently purchased this honing steel and perhaps I can sort out some of the confusion. In short, it does not damage your knives (unless you don't know how to use it), it is for honing (not sharpening), and my box says Made In China. The handle looks and feels exactly like the handles on the knives, and according to Shun's website, is made of the same material.
First, the steel performs like it should, and I have no problems with it's performance, design, or construction. I give it 5 stars for these reasons. The guard is handy for its flat side, helping to correctly angle the blade to 16 degrees--the angle at which the blades are made.
This is a honing steel, not sharpening, as has been said before. When a knife is used, the blade begins to develop small bends in the blade. A honing rod simply straightens out those bends, putting the blade back in alignment again. Of course, eventually the blade will no longer have the perfect edge it once did, and will need to be sharpened (that is, removal of material to make a new edge). This steel does not make your knives dull, jagged, ugly, or otherwise damaged. Unless I suppose, you don't know how to properly use a honing steel.
The box I'm holding here clearly says Made In China. My Shun knives are marked on the blade as made in Japan. That being said, I don't believe that it's of an inferior quality--if you handed me the steel I'd have no reason to believe that it was of a lower quality in things like the handle or craftsmanship as my knives at first glance. Also, I can't say for certain, but perhaps different runs of this product were made in different places. That would at least explain the confusion over where this product is made.
According to Shun's website, this handle is made of "Ebony-black PakkaWood". If it's truly made of some sort of plastic, it's indistinguishable from the look and feel of the knives. The only discernible difference I found is that it sounds different when tapped on, but that may very well be from a different size or shape of tang. There is however, a steel on Shun's website with a Co-Polymer handle. It's product number is 9990, and the handle looks very different from this one, almost like a big black plastic piece. The product pictured is a DM0750.
As a note, I have no affiliation with KAI Corp, Kershaw, or anyone similar (noting my reviewer name).