I didn't stay and watch, because my youngest son was with me. I wanted to. But the mechanic is a good one, and he told me that he "brought all the spokes down to 0 tension, retensioned & trued to <0.5mm lateral." Talking later with the owner, I found they also check to see if any kind of spoke prep was applied, and if not, they apparently put it on.

Though I'm inclined to learn this myself, I gather that in the short-term, it's cheaper and faster to go with my LBS. The combined cost of components, priced here and there on the Web, would be around $330 plus shipping and possibly tax. I'd need a few tools, as well... maybe another $400-$500 total, for new ones. I'm typically riding only 2000-3000 miles/year, so it would take some years to amortize the cost of the tools.

But I really appreciate the replies in this thread, and I thank you all. Very educational and tremendously helpful.

BTW I also appreciate the CC recommendation. Any other trustworthy online wheel sellers that you know of?