There is many ways to fake good ratings.
he is not faking the rating / feedback.....as if he was, audiogon would have already banned him.
if you dont feel comfortable , then dont deal with him.
i doubt you have anything to worry about as like I said, he is a longtime member with tons of feedback.
if someone looks at your profile / feedback you dont have any......so they would be more worried about dealing with you vs someone that has plenty of feedback.