[G.A.S.]

If the pinion and carrier are having new bearings and races installed, you need to re-shim everything.
If your doing just the spider gears, the moulded washers set axel end play, (in and out).
You should check the backlash of the carrier while doing this. If the pinion or carrier need shims, the moulded washer shimming will change . They all work together.
I dont have the specs but I am sure someone will throw them in here.