i have azenis fakens on my 87 gtu... my right back tire is all worn out and others are fine.... does this mean that i dont have lsd so its all worn out??

and can i rotate them to make my 2 rear wheels w/ the most grip....

 

is it evenly worn out? Then you don't have LSD coz if only one wheel is evenly worn out, then that means only that wheel was spinning when you had any wheel spin. If it's not evenly worn out, then you have alignment problems that you should get it fixed so that your next set of tires don't get worn out as fast.

Tire wear is not a way to tell if you have an LSD or not. And I you can move the front wheels to back, and rear wheels to front but sinze Azenis is directional tire(I'm just assuming here but all max-performance tires that I know are directional...) so you can't switch the left tires to right, and right tires to left. If you have wider tires in the rear, you can't rotate them unless you put the rear ones in front and buy new tires that are as wide as or wider than the rear tires that are now on your front, assuming your rear tires fit up front.

 

Azenis are asymmetrical but not directional so left can go to right as well as front to back.

If you want to know whether you have LSD or not just jack up the rear of the car and spin one wheel. If the opposite wheel turns in the same direction as the one you're spinning, you have an LSD. If it spins in the opposite direction, it's an open diff.

Also, just to note, the GTU wasn't offered until 88.