I think what you are seeing in the pictures are pieces of cork used to hold the keys down (or up) during shipping. I've seen this done before, but I'm not sure why it is done. Any ideas?

I would think that too, but look at the D# key. The spring theree would normally hold the key closed anyway, but the cork is as poorly done as any of them. I think they just didn't take the time to trim those corks to the apporiate shape, though the thickness (and thus the adjustments) may be okay. The less surface area of the cork that comes into contact with the tube, the quieter the mechanism is, so this one has some real potential to be LOUD, if I'm correct. As for why keys might be held down with corks under the kickers, it would most likely be to protect the mechanism from damage. If the keys are down, there's less of a chance they'll get bent out of place. I don't think that was the goal here, though.