Are you planning on getting the complete rear pumpkin or just the Limited Slip unit itself(without the gears and no core charge). If you get the complete rear pumpkin, all you have to do is take out the old and put in the new. You don't have to worry about backlash and contact pattern, it's all set. If you get the LSD unit itself, then you have to dis-assemble the complete pumpkin. However, you shouldn't have to worry about backlash. Since, it uses all the stock pieces but, it's a good idea to get it checked anyways.
When I installed my Lock Right Locker, I didn't have to get it check, it was all 'plug-n-play'.
Here's a link of the locker install on my truck. The install took about 3 hours with 2 people. It would be very similar to the TRD LSD unit(not complete pumpkin) install.
HOW-TO: Lock Right Locker install on '00 V8 4x4 tundra