Not true. I have sex linked EE and you can't tell them from my Blacks or from blues. They have all the right stuff to look like an Ameraucana. They ALL carry one copy of the yellow leg gene and that will not express with a first cross.
From what I read on a thread here about him he sell EE so I would err on the side of EE. I would not sell birds or chicks without knowing 100% they are TRUE Ameraucanas.....
I totally agree. To know for sure breed him to a hen with zero beard/muffs. If the chicks come out with a beard/muffs then you would know for sure. If you don't have access to a beardless hen, you can let him got through a molt. That is the other way to know for sure.