There is a lightning ground from the mast to the foremost keel bolt, which does not seem to show any green discoloration. I believe the bolts are all stainless steel. They seem to be the original parts. I would love to send a picture, but my phone does not want to load them to my computer. The only thing I can think of is that a bit of electrical wire got into the bilge, although I do not recall seeing any in there. After a prolonged internet search and asking on this forum, I am going to assume that is what happened. Sometimes the simple stuff is the most vexing. Thanks to everyone who looked at this and to all who replied.