I feel the same on this one as well but I don't really need it :-\ I think it's foam an foil?
They usually are—but unless the same model has been examined, one never knows. I looked around for more info but couldn't find any.
In addition to the unique custom identifier—which, to me, looks like something out of an old s/f movie—I love the case's shape (Space Age!), and of course the keys are beautiful. Being married complicates things, though. Oh well.