What I was getting at, is, if you have a box you need to test, you might not be able to determine what it is/ when it was made, unless it still has a visible OEM part number which you can reference back. And it is even possible (a guess) that during the switch-over, that some cars harnessed for 5 pin boxes actually / functionally got a 4 pin box off the line.
So you might in theory, pull a Mopar OEM box off a "known" early car, test it and it shows bad, only because actually it is functionally a 4 pin box.
