The door panel in the picture is part of the SECM (Shop Equipment Contact Maintenance) body, as it has the lip on the top that goes behind the roller door. If it had a hazmat placard on it it would go to the BEOD (Body, Explosive Ordnance Disposal). Might be a couple others it would go to as well from the same manufacturer.
They aren't very common, as most people with the bodies need to doors for everything to match.