I had read that thread but it wasn't much help (other than positively id the column as Caprice due to the chrome knobs). I saw at least one reference to a lock ring, which the Caprice column does not have. The telescope feature is operated by loosening the horn button and then tightening.
This is getting to be a real mystery. Complicating things is that it's very difficult to remove the hub. One hole appears to be stripped and it doesn't want to budge from the splines. If I could post a photo of the old switch, I might get some help or part #s.