To .001”, yes. It is still important to use paint for contact pattern. In this case the pinion had been previously shimmed incorrectly. This procedure helps to get you back in the ball field and hopefully avoid having to pull it back apart for shimming multiple times.
Won't that ideal number change as the gears wear down? And if you've swapped in new bearings, won't that ideal number also change to account for minor differences in bearing clearance?
