i had one in my last tj. got it used for 180 shipped from dei racing through ebay.
the difference is in the internal spring rate. mine had a brand new set of black springs.
it was locked up real tight. it would almost never ratchet. i was told they could be changed out for softer springs, like a detroit soft locker would have. they use a real soft spring rate for racing. it would unlock really easily. i was also told some use a weird ring and pinion gear, others do not. depends on how it was made. mine used standard gears.
im no locker expert, just what i was told?? take it for what its worth.