I'm currently trying to repair a hinge on a Norcold NB411 2 door but I'd bet the decor panel is similar.
The panel sits in a track formed by the top and bottom plastic trim. There is a removable trim strip on the left and right side of the door. Removing one of the side trim strips (they are just pressed into a center groove) will allow the decor panel to slide out. Mine has no adhesive on the decor panel. The top and bottom plastic trim strips are glued to the foam core of the door, so don't try to remove those strips.
Of course all of the above assumes that your Norcold 1200 door construction is similar.
Fred