By the way, don't worry about it. Even if the hubs never unlocked again, it wouldn't do any harm. The late-model Pathfinders have the same front diff and transfer case (in the SE trim) but have drive flanges instead of locking hubs (bascially hubs that are always locked) and therefore the front diff and driveshaft are always spinning for the life of the vehicle. The X could tolerate the same with little more than a small mileage penalty. If the rear diff can spend 100% of it's life in motion, so can the front.
Brent