Depends on who you ask and what rear is in the jeep. Some say if you have a D35 don't lock it. At this point in time I am running a D30 with a truetrac and 4.56 and a D35 with Detroit locker and 4.56 gears. I have no issues with it being locked and have not broken it yet wheeling.
IMO I would look at the price of doing a TT both front and rear and matching the 4.10's in the rear if the cost will be the same as just locking the front and doing the rear gear in the rear. You have to figure if they are going to pull the front apart to lock it as well as do the regear in the rear you are adding cost to the project for 2 regears.
IslandTj on here is running TT front and rear and stands by it. Had I not bought the axles I have now already done for a good price, (over half less than regearing and TT) I would have gone that route.
98 TJ 4.0L, 5spd, 4.25 Zone lift, D-locked D30/D35 w/4.56 gears, MCE GEN I Flares, 33" Trxxus ATs, Engo 10K# winch, rear disc brake conversion.
My idea of help from the man above is a sniper on the roof.