I am still waiting to hear from the parts places which exact turn signal switch belongs in a '67-'68 tilt column. But I have discovered this info. Most columns came with the DELCO switch. That one uses a 'D' shaped hole in the switch cover. The other kind is the BOYNE style. That one uses a round hole in the switch cover. So since my cover has the round hole I would use the BOYNE style. GM discontinued that but several aftermarket places have produced them. This style is about 2 to 3 times as expensive as the DELCO style and harder to find. My problem is which exact part number is the right one. There are several part numbers for tilt, non-tilt, w/cornering lights, without, etc, and they all use different numbers so it is hard to see what interchanges. Worse, they all look the same. But I do see that the BOYNE locates the hazard button on top of the switch vs the DELCO which locates it under the switch. This would account for the different hole locations on my switch covers in the above pic. Once I can track down the exact part number I need this column will finished.