The rotors look OK, as long are aren't warped (this would make the brake pedal pulsate during braking).
The first 2 bolts to remove are the ones with the rubber gaitors behind them. These hold the caliper itself on. The other two hold the caliper mounting bracket on and only need to come off if you are servicing the rotors.
There is a small metal prong attached to the brake pad on the caliper piston side. It is designed to make a squealing noise when it comes into contact with the rotor. It's job is to let you know to change the pads BEFORE they trash the rotor.
