I figured that if they were on the car when it came from the factory, I want them on it now. Fortunately, they are cadmium or zinc plated, so unless they are in really bad shape, they clean up quite nicely. That, and a quick wipe on the lead with lacquer thinner and they look almost brand new. So what if they don't work as long as they're not shorted. When I did the ones on my '51, I tested them (I have one on the generator and one on the oil pressure sending unit) and they both tested out in the mid .20's microfarads (just like a regular ignition condenser).
Curiously. the original invoice (which I also have) shows my car came from the factory without a radio., but it still has the condensers. I figure that the engine assemblies were completed and installed well before the optional accessories were installed, so all of the engines got 'em.