The overall design of the ComKey 416 system, with others, was to protect the general public from the dangers of central office line voltages. I can't say for sure, but I believe that the intent of the 416 was to eventually be a user-installable system.
True, the hardware is very rugged and resilient to improper wiring. My fingers are crossed that no harm was done. From what you have described, the extent of your testing/troubleshooting was limited enough to where no harm may have been done. Had it been left connected like this for dozens of calls, then there may be room for concern. Something tells me that if a 1983 vintage phone lasted this long, you should be fine.
Please check back and let us know how you make out.
