Freshly turned rotors are the way yours should look when you install new pads. They are smooth, shiny, and very flat. If yours are grooved like a record then they need to be turned. You can measure them with a caliper to see if there is still enough metal to have them turned. I know the measurement is in the repair manuals but dont have it off the top of my head. I will try to look it up later.

96 T100 4x4 - 35's, 4" SL, 2" BL, 4.88s, ARBs, custom bumper & E9000 winch, etc.
99 F-350 4x4 superduty supercab turbodiesel longbed