You pretty much have the idea. Check all of those things plus have a good look with a bright light at the bore and chambers. Also take a look under the stocks at the springs to see if any of the springs look like they have been modified from factory condition. It's no reason to reject a used gun but it might help you talk a little better deal if you were required to put money into the gun before it would work correctly.
Hope you get exactly what you want! I'm all excited waiting to pick up a gun myself. It's a stainless ruger blackhawk in .357 magnum.