Missing Locking Lug Key

My newly purchased 98 Z28 has a set of C5 rims on it. Unfortunately, the car didn't come with the anti theft lugnut key, nor any code number for a replacement. I had this problem a few years ago with a Ford Probe and the dealer had a set of master keys. I haven't found a GM dealer yet who has something similar for GM locks. Other than trying to have someone bust them off with a socket, are there any other suggestions?

Most of the larger toolmakers like Craftsman and Snap-On have special impact sockets that are designed to thread backwards on the lug nut and get it off. I tried with a Craftsman set, then gave up & hammered a regular deep socket on there. You ruin the socket but it's also fairly easy. Best thing to is put an extension in the socket and use a brass mini-sledge/hammer to pound it on. If you're using a steel hammer put something over the end of the extension or you'll ruin it.

If you take it to a shop I'm sure they could get it off as well, for a price. I have a friend who used to work in a tire shop, they pounded sockets over the lock nuts the same as the rest of us.