Hello, I want to buy a wusb54g v4 adapter. I've searched around and it seems that one way to check if it's v4 is to look at the back of the adapter. Yesterday I visited a local store and checked a shrink wrapped box. The serial number was written on it, but I couldn't find any reference to v4. The salesperson didn't want to open the box to let me take a look, which I can understand. So my question is how can I properly identify version 4 of this adapter? Do I really have to open the box to be 100% sure?