[Ford Falcon XR6]

Hi everyone just wondering what company does aftermarket LSD's for au falcon's ?? I had my Xr6 HP Au3 sold to me with the salesmen telling me it has an LSD which i later found out it doesn't (No lsd tag on diff) or at least it doesn't work. I though it's a little silly buying a whole diff when all i need is the centure anyone know who does them ? Hope it's still mostly on topic

Cheers Lorenz