To my knowledge the ones pictured are 71 and 72 types because of the round connector style at the end of the orange wire for the auto seat back release system used behind the right kick panel only. 73s used a larger rectangular connectors for this and fed the seat solenoid wiring from both the left and right kick panel areas . 73s also have a different connector to the main harness above the relay panel. To my knowledge these are some of the differences. Other members may be able to point out other differences.