This version of the vent controls has a detent "click" and the end of the range - correct? The version I had in my 68 car did not have this feature and was significantly more flimsy...
Yes, the version that I'm using (the one that came out of a 66 Duetto) has a definite "click" at both ends of the controller travel.
I prefer that one over the later design.
However, after my initial writeup of the later design, I did go back and inspected my 67 controller again. It looks like it does have an isolation plate between the 2 levers that should keep the adjustment of one lever from effecting the position of the other lever. But because of flexing of the sheet metal, the isolation plate wasn't anchored properly. So, it ended up not isolating the 2 levers from each other. That said, there still isn't any feature in the later design that would provide any tactile feel when you adjust the levers to the end of their range. So, I still think the early design operates better.