I may have misunderstood his question. I see the original question was about changing the switch, and I was thinking he just needed to replace his lever. I was also "assuming" he had a tilt, since he really didn't say.
If you're "switch" is really broken, there isn't any difference in the turn signal switch whether it has cruise or no cruise. You got me curious so I looked up the part number of the switch. The turn signal switch is the same from at least 76-81. So, I looked at one of my 79-81 columns, and took a look at the switch. The provision is there for the screw-on lever, even on the 79-81 switch. BUT, because of the box on the side of the column, the positioning of the screw-on lever would not work with it. So, with that column, you will still need the push-in lever.