I've seen a number of stones being sold by this guy, and you're right, his numbering system and the odd use of some expressions reminded me a lot of 330mate, but then you see that he's located in Alburquerque, New Mexico. Is he 330mate's US distributor?!

It would be great for someone just to ask him straight out whether he will accept a stone for return AND a full refund if it doesn't perform well. I mean, I'd think for the price he's charging he would include that kind of service, but you can never tell.