A vehicle seat part, such as an armrest, includes a blow molded surface structure with insert molded metal plates. The insert molded metal plates are provided at each side of the blow molded surface structure and include a stamped part with passage openings. A pivot pin may extend through one of the passage openings and be insert molded with one of the metal plates to form an armrest pivot. The passage opening may instead from a pivot bearing to receive a pivot pin. Another of the passage openings of the same metal plate may form a plastic passage allowing plastic to pass through the metal plate and form an engagement surface at opposite sides of the metal plate.