The IPv6 ready logo means that the product certified has passed the tests according to the logo requirements. If a product is not on the logo list, it does not mean it can’t be used. Getting the logo certification is an option a vendor can choose, not a must. So if a product is not on the list, it simply means the vendor has not applied for the logo. It can still have great IPv6 support. You will have to test any IPv6 product in your lab anyway.
Hope this helps, Silvia