A dork disc is the spoke protector on the rear wheel between the freewheel and the spokes. It prevents the rear derailleur from catching ont he spokes, which can cause big problems not only to the wheel but also the derailleur and derailleur hanger. They serve a purpose, but only if you don't know how to adjust a rear derailleur properly.

I did say earlier that I would touch up carefully. However, with many, many small chips, sometimes touch up paint can look worse than chips if not done well. If you are not happy with the initial touch ups, for a "rider" I may consider just treating the rust and then touching up the chips with clear nail polish to prevent any additional rust. One trick is to apply the touch up with the end of a toothpick and stay only within the chip, not overlap onto the original paint.