In a previous picture of the back of the car, it showed that you have a 73-74 style rear valence on the car. The 1970 valence used different brackets to mount it to the car. Once the bumper is installed you can't tell the difference anyway so it's not a big deal.
I just wanted to tell you that you need to remove the triangular lisense plate bracket from the valence. The 73-74 cars used that bracket to space the plate out farther due to the 5mph impact rules. If you leave the bracket on the valence, your plate will stick out too far and not look right. The 70-72 bumpers are mounted closer to the body so that bracket isn't used.
