Appraisal Unpermitted den part of sq footage

[Mark Futalan]

Found a house that is 2/1 with an unpermitted den. The house is listed as 1,000 sq ft but that includes the unpermitted den. Do appraisers include that unpermitted room in their appraisal or do they go by public records? Home is surrounded by million dollar homes and is listed at 709k. Similar house and assumed da ft sold for 850k fixed up but that’s assuming the den is part of sq ft. What are our requirements to get this to code or permitted. As a buyer, should I be concerned?