You do need to stake them in. I made the mistake of not staking the pins on my El Camino and the drivers side upper pin would work it's way up every so often and I would have to take a hammer and tap it back down on occasion.
If you were going to install the pins while the hinges were still off, I would guess that you could just lay it on something heavy and hit it with a hammer or maybe for a better look, you could just use a press and flatten the end slightly with that. It won't take much.
Good luck!
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