I am about to buy a 2006 zx6r and the guy says there is a full yosh pipe on it. It doesn't have a power commander on it though, which makes me think either its just a slip on, or its not a good bike to get since it would run lean. How can I tell if it is a full yosh exhaust?

EDIT: Will the header say yoshimura or something like that? Or will it look the same as the stock? Is there any type of catalytic converter that would have been removed with a full exhaust?