Does the standard 9" diff look like a detroit

Since the locking unit is internal, there is no way from the outside to tell by just looking. The locker does not have a cage with spider gears. If you took out the axles and looked in the axle holes, you could see clear through, no cross shaft. (Handy for changing broken axles on drag cars) This is not the case on the later lockers. The famous clicking was on the early units only. Everything manufactured past 1969 was virtually silent. (I had three)

 

If you jack up one rear wheel and twist the raised wheel back and forth it doesn't act like a car with a differential.
jimbo