Gears & Axles - Questions about my 10 bolt???

I have a 94 camaro that was converted to be an LS1 car. The car was originally a v6. I am looking to buy a eaton posi differential for my 10 bolt and i'm not sure if its a 26 or 28 spline??? Also will i need to purchase anything along with the differential to make it work since my 10 bolt was suited for the v6?

1988 and earlier had 26 spline,1989 and later have 28 spline.
Except for lack of 'positraction'(in most cases-some V6 got 'posi') and disc brake setup,rearends are the same as the V8s'.