Need help, appraised square footage is different than tax records

Could someone help me? We are in escrow and our appraisal came in at the purchase price but is based on square footage that is 160 sq ft bigger than tax records. Do appraisers actually measure the home? Will this affect my future resale value? I am assuming I can only advertise square footage based on county records (or expose myself to some potential liability regarding misrepresentation).  any advice appreciated!