Have fun, fellas!
If it's anything like the times he has come to Righteous Guitars and the videos I've seen, he does a casual clinic followed by a meet 'n' greet / signing session. Paul just wings it based on how he's feeling and what questions the audience asks.
I can't recommend it highly enough.
Check with CME about bringing guitars, but what Righteous did is check in your guitar at the beginning and give it back for the signing session. I imagine Paul carries a gold paint pen everywhere he goes. I've had him sign my headstocks, but if you just want your backplate signed, it would certainly be easier to just take it off and bring it with you.