The only difference I have seen in transfer plates of the same year is the depth of the channel that feeds the rear servo. In the pic below you can see that the channel on the right is considerably deeper; this allows higher flow for a quicker release which is beneficial during a manual 1-2 upshift but risks servo damage during application.

The pressure relief ball is intended to relieve pressure over 300 psi which can occur when Reverse is selected when the trans is cold.