Nicely done, indeed! The key to this -- and the hard part to begin with-- is having accurate plans/drawings to work from, and an easy material to work with. The rest is just careful execution. The fact that they used basswood made it a lot easier; it is light and soft, and easy to shape. A little harder than balsa, about like pine without the grain issues. Also, because of its relative porosity/light density, it is acoustically pretty "dead", like the seller said.
Making that out of Palm wood or ironwood or blackwood would have been a nightmare ... and it would be resonant!
:scratch2: I don't see why one couldn't mold and cast these out of acoustically-inert plastic material. Could be cheap, and might sound good, if you chose the right material. Would also be lightweight, and could be done in much higher numbers than that painstakingly harnd-crafted wooden artwork!