NEED HELP - Tim Duncan shoes, what do I have??

[BIGSTIG]

I do noy know much about basketball shoes, but I was going to the Bulls vs. Spurs game on 3/20/08 and new I had incredible floor seats next to the Spurs bench. Anyway I picked these shoes up off of ebay, I was told they were game issued shoes? I got Duncan to sign one of them (the right shoe) after the game. He signed, and I counted 1 autograph, and it was this shoe. Anyway wondering if someone who knows NBA shoes can shed some light. Any idea on a value?

Thanks