Here are some photos of the second set. They came with a complete set of GM A-molds I bought from eBay. I believe they are supposed to be off an original '95 ZR-1, so they are older tires than the other set. Tread depth on these is just a hair over 1/4", so they do have a little more tread than the other set and visibly they do appear to have more tread as well. When I removed them from the wheels, I noticed one had been patched.
http://i20.tinypic.com/vr4msj.jpg
http://i24.tinypic.com/90ruop.jpg
http://i23.tinypic.com/120l4qr.jpg
P.S. in both cases, the tires look fairly dirty. While they could definitely use a wash, the flash seems to make them look much worse than they really are.