You seem pretty determined to buy from them.
To me that statement smells of bovine excrement. To me a genuine answer would be, yes they are genuine. I don't know about Sony, but I have seen authenticity certification on one vender's site for E-Fest batteries. All the stuff about using them personally, and the exaggerated claims about performance seem to fall into the class of too much information being offered, which in my opinion is often indicative of a lie.
Anyway, I'm almost certainly reading too much into this. Buy them, don't buy them, it's up to you and your medical insurance.