Do I have a sure-grip or not?

Trying to verify whether or not the 8 3/4" rear end in my Dart GT is a sure-grip. With the rear axle up on jack stands and the transmission is in neutral. When I rotate the passenger side wheel, in the forward direction, the driver side wheel also rotates in the same forward direction. If my memory is correct, this means it IS a sure-grip. Correct?