I don't know much about anti-sqeel, so can't help you on that question. However, to tell if your "disks" are worn out, you should measure them and compare to the minimum thickness specified in the FSM. If they are thicker than min, then you're good to go....if not, then replace. If you have disk fronts, then the min rotor thickness is usually stamped on the rim.
CRC synthetic caliper lubricant.
What I do is...
Buff all mating surfaces. Sand the rust off the pins. Thoroughly clean the piston tops.
Coat any surface that touches another surface with the lube. (But not the caliper-to-rotor surface, :duh: )
THOROUGHLY coat the pins with lube.
Rarely do I ever have a brake job come back for noise.
Your pads will last longer and wear more evenly this way. too.
Bevelling the leading and trailing edges of the pads is a necessity for big Chevy's, like 3/4 ton+