Chrysler Electronic Ignition No Spark

A 5 pin box must have a 4 pin ballast

A 4 pin box can have either 2 or 4 pin resistor

A box with 5 physical pins does not make a 5 pin box. The 5th pin may be unconnected. If it is made in last few years, or aftermarket (not Mopar OEM) then it is most likely 4 pin

If you take an ohmeter and test resistance from the 5th pin to all the other 4 and ground, then reverse the probes (polarity) and do that again, if the readings are all "open" (infinity) then you can be sure you have a 4 pin box