Front Diff Actuator

95 sub, front differential actuator:
Which type is the "updated" type of actuator?
The 5 pin plastic one or the 2 pin metal one?
I have both and need to know which to install . I have the 5 pin wiring harness installed already ( came that way) but have replced the front diff with a 94 front diff with teh 2 pin in it.

Thanks,

W-