As others have stated the 70-71 style bumpers will bolt up to a 1972 model
However, as an FYI - as usual the 1970 is a one year only part. For 100% factory correct parts the 1970 bumpers have details that are different from the 1971 bumpers.
Also all years 70-71-72 use a different corner bumper rubber piece even though there is only one reproduction offered as correct for all years