To start with you ask questions and do your research before the transaction as the guys said.
2nd you never ask the seller.you dont know him/her and you may be speaking to a person that has a very good reputation and a question like this may insult him/her.there are people here with nicknames or you may know their company/brand/shop but not their full name.
If its a con your answer will always be yes so no need to ask.
Now to do the research, first person you ask is the builder of the machine.they can spot a fake from 100 yards. In your case an email to stigma would have solved all your questions.
IF and i say IF theydont they dont reply in 2 days (in my experience within hours ) you ask in the forum.most of the buiders are members here and lots of people have the experience to give an answer.
Now if Athena (Athena is female by the way)sees it and tells you its a fake you would be in deep shit.
so keep these in mind for your next sale or trade.