not sure what the differences are, but the reproduction harnesses do have different part numbers for 68 and 69. I don't really know what would be different, as the dash clusters are pretty much the same, radio, etc....could be something as minor as different color wires used...I know the 70 harness is different as the ignition switch and flasher/hazard switch got moved to the steering column...maybe find wiring diagrams for both and see if you can find any differences...