Ignition tester

There is likely no way to tell if you are checking some unknown box. This is because some 4 pin boxes have 5 pins, and they will replace older "true" 5 pin boxes

Only way I know to be sure is to look up a 4 pin wiring diagram, so you know for sure "which pin" and if the box has one, check continuity from it to ground and the other 3 pins. Reverse polarity on probes and do it again....... If everything shows open, it's a "4 pin" box.