A Lockrite is a "lunchbox" style locker that goes inside the carrier. If the carrier you are buying has a Lockrite inside it, I would not install it. The stock axle shafts used in a Dana 35c are barely adequate for 33" tires when no locker is installed. When a locker is installed, it's not really adequate for any size tire. A locker can double the load a single axle shaft sees when you're offroad and they're just not designed for twice its rated load.
Generally speaking, a stock Dana 35c axle should never be locked. The only safe way to install a locker into a Dana 35 axle is to upgrade it with a Super 35 kit that replaces the OE carbon steel 27 spline axle shafts with hardened alloy 30 spline axle shafts. A Super 35 kit also includes a choice of full-case locker like an ARB air locker, Detroit Locker, etc.