[LONGHAIR]

If all you are doing is changing the carrier to install a Detroit Locker, you don't even need to touch the pinion....but you do need to get the backlash correctly re-set. It should be set to Exactly where it was....pretty much reguardless of what that actual number measures to be. So to that end, you must check it before you take it apart. Swap the ring to the new carrier and adjust the shims to get the same measurement as before. Do not bother the pinion, as far as that goes, you don't even need to disconnect the drive shaft.
The "contact pattern" is irrelevant at this point. It will have worn into whatever it has now and you must not change that....damage will occur if it does.
I said "pretty much", before in the pre-removal measurement stage of backlash...because there is alimit here. If your pre-removal backlash measurement is too big, I wouldn't spend the time or money on these gears. You cannot "just tighten it up"....That will destroy it even faster.

Did I mention the backlash has to be exactly where it was before?

One more thing......Synthetic gear lube