Hi Michael, welcome to the forum! Nice to see another "Chevy man" out there.
Now, as for the door hinge question, it's been a while since I did this, seems to me step 1 was "off with the door!" Before removing the door, scribe alignment marks around the hinges so you can put it back on in the same place. Enlist a helper or use something like a jack stand to help support the weight of the door during removal/installation.
Now you should have easy access to the pins & bushings, tap them out and install your replacement parts. While you've got things "disassembled" , take a look at the condition of the door check, (reverse "S" shaped piece of round bar on the top hinge) sometimes they break.
When I replaced my pins/bushings I was also replacing the doors (rust! - mucho salt on the roads here in Canada from Nov - Apr) so they were off anyway. I'm pretty sure they need to come off to get access to drive the top hinge pin out, due to the curve of the body shape in this area.
One other thing I have seen on occasion - small MIG welder tacks on the bottom of the pins. These have to come off before the pins can be driven out.