An local automotive electrical shop that I thought had disappeared is still in business, so I took my alternator there for testing after pondering some of the comments here. The owner has a cool test rig (that his grandfather built) for off-vehicle testing. He told me that it was not "putting out", so he opened it up and found that the regulator was bad. $40 and about 20 minutes later, I had my alternator repaired and re-tested to assure that it works.

I re-installed it and now all is well again - I'm now getting 14v+ at the battery and 12.5v at idle. Also, my ammeter shows positive current flow.

If anyone lives in my neck of the woods and wants a great recommendation and the name and address, I'll be happy to provide it.