Hi, I'm pretty sure that is a legit signature. I have a copy of Captain Victory #3 that I personally had Jack sign at a Comic book store here in Las Vegas when it was released and your Signature looks spot on.
Originally Posted By: Nutmeg CoinAnother reason not to run no reserve auctions on ebay, they are almost always losers. Some sellers seem to get elated when their material fetches Greysheet bid there. Either they would have to buy at firesale