well the one in the pic was probably groomed and made to look all fluffy for the photo. It's very possible you have a mix on your hands. For them to charge you extra for his papers isn't right. It sounds like(if he turns out not to be PB) that they told you he was PB when he really wasn't--since PB's sell for higher prices than mixes and people will more likely buy a PB--and thought they'd make some extra money by charging for papers that probably aren't for that dog anyway.
Did you buy him from a private breeder?