Bob--

Thanks for the advice and I did exactly what you advised. After confirming that it was the mag itself that was continuously shorted even (I manually turned the engine over several turns while monitoring the resistance to insure the contacts weren't closed), I removed the flat cover on the back of the mag. This is what I saw in the inspection mirror. The camera is looking down at the mechanical fuel pump, and the image in the mirror is looking toward the front of the aircraft. You can see the condenser at the top of the mirror, the points and cam in the middle, and the P-lead connection at the bottom. That black spring steel to the left of the brass screw is where the P-lead contacts the mag - you can see a little brass-colored circle at the point of contact:



I rotated the engine manually until the points opened and re-checked the resistance. It was still less than 0.5 ohms with the points open.  Then I unscrewed the screw near the bottom of the mirror and determined that 1. The condenser wasn't shorted, 2. The black spring steel P-lead contact wasn't touching anything, and 3. The wire going to the coil (yellow lug at the very bottom of the mirror), WAS shorted to ground.

Bottom line: I removed the mag from the engine, bagged it up,  and delivered it to the A&E for return to the shop that "refurbished" it. AFAIK, the shop did not change out the coils.

It's hard to get good help these days /sarc