@apanrune , I think you are absolutely correct. This signature has surfaced many times, sometimes from people that are not looking to sell. They (all?) say they were attendees at the New Jersey event. I’m sure it is an earlier style.
Here are a few more examples:
Erika’s Clefairy: www.elitefourum.com/t/autographed-signed-pokemon-cards-ken-sugimori/12830/45
Blaine’s Charizard (previously purchased and then sold by TCA Gaming - claimed to have seen a photo of the original owner having it signed, but unable to find the photo unfortunately): www.elitefourum.com/t/blaines-char-2-132-1st-edition-authentic-autograpgh/26797/5
Chansey (See third image in post #5, owned by a forum member from years ago): www.elitefourum.com/t/tmb-2000-lucky-stadium-card/13140/1
Giovanni: pkmncollectors.livejournal.com/14780190.html
I also have pictures of:
– Surge’s Pikachu (Japanese, no pikachu drawing)
– Mew promo (no pikachu drawing)
– Rocket’s Mewtwo
– Lapras
– Jungle Pikachu
– Nidoking
I was hoping that the community would continue thinking these are fakes and manage to pick some up cheap 
– but they are rarer than the signature everyone knows. The Machamp is the first instance I’ve seen for sale in a while - thanks for sharing it.
Edit: here is the blastoise for anyone interested: www.ebay.com/itm/133583322202
No wonder it slipped under the radar for me - “signed by artist” isn’t in my search terms