I wouldn't lose any sleep over speculating what the K4s will have or won't have. If and when Amazon officially announces them, it will probably be a few weeks afterwards before they can be ordered. I would think K3s would still be around for purchase for a while after the K4s come out. Certainly there will be a lot of people selling their used K3s to upgrade. So you shouldn't have to worry about being able to get a K3 for quite a while.