I think I've got a book he signed somewhere. I'll take a look and see if I can dig it up. That does look sweet, tho.
Thanks - I did a Google search for examples of Jack's signature, and there are a couple of interesting things to note:
1) In every instance Jack uses lower case letters, not block print capitals. First hand, I know this isn't conclusive, as I myself switch between them when writing (hey, I'm left-handed - give me a break!) But when I sign my name, I almost exclusively use -script.
2) The end of Jack's "J" doesn't come up and around, but consistently points downward.
That being said, there appear to be a an equal number of similarities, although those are significant variations.
This may be why CGC doesn't make a forensic judgment, and gives such books a qualified label, right?