Do I have an LS Differential?

[brookierookie]

Hi guys, I'm new to the forum, and am changing my differentials for the first time. I have 2 questions:
1) I have a 2004 3.5L V6 Pathfinder SE. There are no markings on the differentials except a big "JS" engraved in the rear diff. Do I need LSD fluid?
2) I've bought Valvoline 80W90 approved for GL-5, and it says "limited slip" on the cover. Should this be ok, whether the diff is a LSD or not?

[180sx]

That should be fine. No problem.

Jose