Yup... Best you can hope for is an older guy that knows his stuff. I had an 86 Laser, years ago, I remember replacing the alternator on it.
I can see that it's sort of luck of the draw... but I can also see a trend of the places that are more trusted than others, for whatever reason. What I've heard here pretty much mirrors what I've heard from other people around where I live. Could be useful information, could be bullshit... but the odds are that there is a reason why more people seem to trust certain stores over others. I was curious sort of overall which store people like anyway, not solely for an alternator.
I looked into rebuilding the thing myself, but it needs a new bearing and possibly center shaft, the kits I've found only have the brushes. I like the idea of trying to have it rebuilt locally, I'm going to look into that.
As far as things being rebuilt in Mexico... In the six years I worked on the assembly line for Chrysler, most of the parts I put on were from Mexico, Taiwan, China, Pakistan... No doubt mass produced in the same environment and manner that you describe. Quality control in that place was a joke. You'd say "Quality" and the foreman would think you were speaking Chinese. "Kwaa-li-tee... What a funny word. Never heard of it."