My advice is don't do it.
Are you getting those steel ones by rugged ridge? They suck and rust like crazy. They are definitely not stainless. And the mounting hardware that comes with them is awful, cheap, and also rusts like crazy. And they're stupid expensive.
So if you put them on, be prepared to need to repaint them anyway. In about two weeks. And keep in mind that once you pop the hinges off the door, you break the factory seal and need to take care when remounting or you'll end up with rust inside the door. And be careful not to goof up the angle on the reinstall, because the likelihood you'll ever get it back if you do is almost zero and your doors will leak forever.
If you want black hinges, the best option--by far, really, really far--is to take your doors off, leave the hinges on, sand the hinges, tape off the hinges, prime the hinges, put about four coats of bedliner on the hinges, take off the tape, and put the doors back on.
There's absolutely no question in my mind.
Read and disregard at your own risk: (http://www.wranglerforum.com/f33/my-...es-125491.html
And you can see how crappy and rusty my RRs got here, just scroll down to see my pics: (http://www.wranglerforum.com/f33/bla...es-128968.html