Hate to break it to you, but the axle code for a Trac-lok rear is 3L08.
The L is the letter which indicated the limited slip differential.
I don't know what P refers to. What did this rear end come out of?
It's a limited slip differential, not a spool or locker. Posi is a GM term, so ford wouldn't use it on theirs. Their name for it is "Traction-lok"