How do you get the hood hinge off a 69 A body?

You will have to pull the Fender to have access to the clips that hold it on

pull, really really hard
there are clips on the pivot pin and spring end under the fender top then it pretty much falls right off.
accessable if you take the splash shield out but much easier with the fender off.

I took one off a car in the wrecking yard that was missing the door, but the fender was still on. Slow going, but I got it off.

Installation with no straight on access to drive the retainers back on might be rather difficult. Might be able to use a socket and some wood as a prybar to leverage them in place.

RestoRick sells the correct diameter retainer push clips.

here's whats under that fender

I tried the hardware store push clips. They were not nearly strong enough. Popped them off the first time I tried to close the hood. Spend the money for good clips.

Read on the for a bodies only forum about using a collar shaft on those in addition to the clips. If the hinges get stiff they can start to walk off the pins.

Mine doesn't look nearly that good

In a pinch I tried fuel line size hose clamps - the good ones, not offshore junk. Been on there for years.