He ought to at least listen to them before selling them. I owned a pair of white van speakers and although they didn't sound great, they didn't sound terrible, either. He already has them, and he might be satisfied with the sound. Well, he might have been satisfied before someone clued him in. I think that if you "know" that something sounds bad or great before you listen, that when you do listen, your brain works to accommodate that "knowledge".
Maybe this guy is a white vanner himself and this is a new sales tactic. If so, I don't think it will be very successful.