I was under the impression (apparently mistaken) that CDL's were Federally regulated. I got my CDL B in Connecticut in 1969 with Air Brakes & Tanker endorsement. At the time a CDL was needed for air brakes.
There certainly was. I was driveing a ten wheel flat bed truck for a local Lumber Company. The local High way department sent a senior driver down and anyone who wanted to be "Grandfatherered" in could get a form to take to the Ct. Motor Vehicle Department and it was added to the back of your license.