Brake corrosion

So my wife told me that my trucks brakes were squeeling real bad first thing in the morning when backing out of the driveway. Ordered new oem rotors and pads and had a buddy of mine swap them out for me. Looks like somewhere in its life, someone just slapped pads on it and didn’t change the corroded rotors. I am noticing that the wear in the rotor makes it look like the pad isn’t making full contact with it, is this normal? These are the fronts, he said he is going to do the rears tomorrow