How in the World???

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.