Not necessarilly.
Lets say you are changing a pinion seal.
Before you remove the pinion nut, you record the torque to rotate, with the brakes components removed, but the carrier/ring gear remain in place.
When retorquing the pinion nut, you torque to 160 ft/lbs at first, then continue in 5 ft/lb increments, until you get the recorded torque to rotate, plus 5 in/lbs.
This will give a good preload, and it ensures the crush sleeve is still functioning as intended.

 

When changing the pinion seal, I always put the vehicle on a lift, then pulled the shaft, used a puller on the yoke, popped out the old drove in the new used a flange holder to install the yoke and tighten the nut till you feel resistance, then about another 1/8th of a turn. Never had a problem that way. But setting up rearends I was taught to check the rotational torque with the ring gear out, plus most 0-35 inch pound beam style torque wrenches will not be accurate after rotating both the pinion and ring gear. It would definitely max out mine and that ain't cool.