Mopar Electronic Pickup Polarity and Rotor Phase

That is not the full story. Polarity reversal also moves the trigger point in relation to the rotor, which is exactly why, in this day and age, we have the term "rotor phasing." Maybe the term should more correctly be, "rotor to trigger phasing"
Thanks for the correction. I didn't think about that (mentioned by Kit), which can be an even bigger problem since the spark could jump to the wrong cylinder post. What I've done to verify rotor phasing is spin the distributor by hand (out of engine) and flash a timing lamp at the innards (cap off). Insure the reluctor wheel teeth aligns with the magnet center when it sparks. If not, reverse the polarity and try again. When doing this, connect the coil HV output cable to gnd, either directly or thru a spark tester.