a locking seam alignment guide may be utilized for attaching a fabric cover to a substrate to form an interior trim component in a vehicle passenger compartment . an elongate ribbon - like member has a longitudinal stitching flange and a longitudinal locking key depending from the stitching flange along a midline thereof . the longitudinal locking key has one of a cylindrical shape , and a triangular shape . the longitudinal stitching flange is one of a flange extending along one side of the midline , and a flange extending along both sides of the midline . the locking seam alignment guide can be stitched to a fabric cover and seated in a complementary keyway to hold the fabric cover to the substrate .