First of all, it is not uncommon for listings to have incorrect info or for county records to be wrong. One possibility is that additions were done without proper permits, and sometimes they are done with full permits, but the county didn't properly update the records.
However, the biggest issue with this listing is that it is probably a rental scam. $1000/mo. for a Willow Glenn cottage is ridiculously low. DO NOT SEND MONEY TO OUT OF AREA LANDLORDS!!! Verify the ownership of the property or the verify the authority of the property manager before considering a rental agreement.