Stabilizer bar

The earlier bar goes all the way around the K member so it will work with either type K member but its end links are out near the lower ball joint. It does interfere with the later model disc calipers if they are mounted to the front.
73 bar threads through the middle of the K. Its forward mounts are more tucked away. Its end links are shorter and attach more toward the middle of the lower arm.
If I had the later K I would want the later bar design.