LSD 05 Prerunner TRD

Question...I read through a few old posts/threads regarding limited slip diff's and from what I gather there should be a sticker on the pumpkin somewhere reading LSD...mine does not have that so...I took a trip to the local toyota dealer and the service rep assured me since I have the RR Diff button on the dash that I do not have limited slip...VIN searches turn up general info on my taco so I was curious if anyone here may be able to elaborate and or set me straight. I am asking since my plan is to service the diff and change engine oil tomorrow...just don't wanna burn up my rear end because of the wrong oil. I bought 80/90 oil today that mentioned nothing about limited slip so I figured I was safe...however assumptions are what they are. Thanks in advance all,

 

if you have locking rear, definitely no limited slip, no friction modifiers necessary