If it's 8.8, All '87-'93 Mustang 8.8 were a lockers, if its a 5.0 car. and all GT's were 5.0 and had quad shocks, the mount for them is on the housing top behind the back plate.
I'm not sure, but I believe '86 and older were 7.5 with a big counter weight on the pumpkin.

Pat