Okay Coelcanth and CV-6, I know you can give me some details.

I know from reading CR threads that older record headsets have a <c> on the lower cup. This <c> comes after Campagnolo. I believe catalog 15 (1967) to be the first catalog to show the record headset with embossed print. In the catalog and all subsequent catalogs you can see "Brev. Campagnolo Italy"

1. What year did this <c> appear and disappear on the lower cup, exactly?

I know from looking at parts of my own that some Record headsets have a <c> on the bottom of the crown race and later ones surely did not.

2. What year(s) did this <c> appear and or disappear on the crown race?

3. Lastly, did the profile of the crown race change? What I am talking about is the part you can see when the headset is mounted. For most headset it is a nice flat taper. I have an old crown race that is rounded and bulbous, just curious if it is a super early record crown race.

Sorry if I am delving too deep into the unknown.