Just as an original finish adds to the value of a piece, original condition also adds to its value. This refers to the overall state of the piece. If the piece has the same features that it did when it was produced or still has the original hardware, shelving or drawers it is considered to be in the original condition.
If the hinges have been removed, new shelving added or the drawer pulls have been replaced, it's no longer in original condition. As soon as something has been removed or added to a piece, it is less valuable.