If they show any damage, replace it.

Caliper Fluid Seal Damage
Caliper Piston and Cylinder DamageAir Cleaner Housing Installation
For ZX1000JD/KD, be sure to install the pad [A].
Install the clamp bolt heads [A] inside as shown in the
figure.
Install the air cleaner housing on the throttle body assy.
Push in the ducts [B] touch the stoppers [C] of the throttle
body.
Be sure the hoses are routed correctly ...
Seat Cutter Operation Care
1. This valve seat cutter is developed to grind the valve for
repair. Therefore the cutter must not be used for other
purposes than seat repair.
2. Do not drop or shock the valve seat cutter, or the diamond
particles may fall off.
3. Do not fail to apply engine oil to the valve seat cutter
...
Stem, Stem Bearing Installation
Replace the bearing outer races with new ones.
Drive them into the head pipe at the same time.
Special Tools - Head Pipe Outer Race Press Shaft [A]:
57001-1075
Head Pipe Outer Race Driver,
55 [B]: 57001
-1446 or Bearing Driver Set: 57001-1129
Apply grease to the outer races.
...