The difference between a den and a bedroom is not going to change your value substantially if at all. However, a closet isn't the only item that makes a bedroom. The room must also have a window. Appraisers also calculate above grade (ground) and below grade s.f. differently so that might explain the variance on s.f. Wishing you the best of luck.
If the value you were looking for was not obtained, then you can look at fighting to get it corrected. But note, correcting the report may still not change the value significantly in your case as it may for a 3 versus 2 bedroom home. Good Luck!
Lisa Miller Scott
Sellstate Dominion Realty
1st Mariner Mortgage