Thanks Joe. That was a great event and had many other cars other than the W113s on display. I learned a lot.
The only difference that I know of is that some had the fan speed control where my "defrost" label is. The coupes and cabs had that speed control on the dash to the left of the radio.
Unfortunately I didn't need one at that time. Wasn't until I installed my freshly plated one and......POP >:(went the 6mm stud on the back side. The face is pot metal and the stud is steel. Not sure how they joined the two back then. When I examined the failure point, it appears that the stud had significant corrosion. Not sure if that occurred during the manufacture or when it was rechromed.
It is secure for now but not sure for how long. Funny how work on old cars go. Some days it is a breeze. Then some days seems like everything goes wrong.