Another vote for leaving well enough alone. My experience is it's much easier to change the seal with the carrier in the housing, the support from being bolted up helps with breaking the pinion nut loose.
With the above said when I had my new to me, used 4.10s ready to install it was an easy decision to bolt it up and try it. If it leaked, then change the seal. Good news is no leaks with over 2,000 miles so far.
RonR
