Rearend Axle Tag Help

[Black1987]

My friend was cleaning out his garage and had this rearend in way. So, he called me to move it, and then said take he didn't have a use for it anymore.
Weird looking tag, little confused 3:08 Locker right?

Top row reads: WFC R- 3K20
Second row is: 3L08 A75 S271D

 

[Mustang5L5]

3.08:1 ratio with a limited slip differential (aka traction-lok)


The other numbers are date codes, but indo not know how to read it.

 

[Black1987]

Thank you