Yup, I did the same thing with my CS -- it also saves time when swapping wheels before/after autocrossing.

If you want to buy a second Porsche lock socket, just take your current socket to the dealer's parts counter. Show them your lock socket and ask them to order you another one. There's a code inside the socket that they need to get the right one. Also, if your dealer has a hard time finding the listing for the lock sockets, tell them to look under Cayenne parts -- for some reason, that was the only place the parts guy could find them (hopefully Porsche will fix this in PET soon).