How in the World???

BillGrissom said
The answer "it depends". My 1964 Valiant convertible has top nuts on the pivots, my 1965 Dart has the lower release clips shown. But, I don't know that both are original. The Valiant especially had much redneck-engineering, like an unknown radiator and "Honda" battery. If a top nut, there will be a flip-up cover to expose it. Same deal on my 1996 and 2002 minivans.

64 and earlier bolted on. That's A, B and C bodies, and pre ABC, too (my 49 Dodge's wipers bolt on). 65 started using the style shown in the OP. Again, A, B and C.

63 Valiant

65 Barracuda (yes, I need to replace the windshield gasket; have one, just been too lazy to get to it)