69 was the last year for the flasher switch on the dash. 70 was the first year for the steering wheel lock and flasher switch on the column. I think the 70 column with auto shifter is pretty much identical to the 71 column except for how the flasher switch operates. The 70 flasher switch is activated by pushing it in, however people were accidentally turning it on while exiting the car so the 71 switch was activated by pulling it out. The two switches are interchangeable so if the 70 column's switch was ever replaced it would probably be with the 71 and later switch.