I found some of the decoding info in my manual for my rear axle tag.

WDJ-C = gear diameter (8), differential (locking), ratio (3.00:1)
L00 5CE 906 = ???


What is the difference between "locking" and "conventional" differentials?

Is one preferred, more rare, worth more than the other?

It's on a C4 auto


Thanks!

How bout those Irish

 

In a conventional, or "open" differential, power from the engine takes the path of least resistance. Meaning the wheel with the least amount of traction is where the power goes. In a "locking", or limited slip differential, as soon as the one side starts spinning there is a mechanism that engages to apply power to the other axle.

As to the next three questions: Yes, Yes and Yes.