No, he wouldn't be right. He would have no evidence for it. He had absolutely no reason to believe in them. He just happened to get lucky. I'd like to qualify this statement by saying I don't think anyone in history has every been that lucky or ever will; this is just a mind experiment.
If you had to believe what he said, you'd have to believe what everyone said, and you'd be making a nigh infinite amount of bad decisions for almost no good decisions. There are better ways to make decisions in life than listening to some random persons creative inventions; it's called science.
Believing in religion is like buying an infinitely small bit of a lottery ticket for all the money in the world; just not a good bet.
BTW, I don't have to disprove something only supported with bad evidence. It's not a matter of belief in no God; it's a philosophical approach to life to reject things out of hand that have only bad evidence in support of them.