That's the item, Chris from VA. :-)
MLeake -- I noticed that the built-in sights (which are nicely aligned) show that the dot is above and to the left slightly when I'm dry-firing up close. At first I thought that was a bad adjustment, but it appears that they are adjusted perfectly for 50 ft. I think I'm just going to leave them there and train to make the proper close-up adjustments when shooting.
It sounds as if they make a huge difference when you have bad or weak vision, or a poor-visibility/low-light environment, but not as much for those with 20/20 vision in a clearly visible environment. I'm planning to practice both using the dot and not using it; don't want to be completely dependent upon it. But it *really* makes a difference in the quality of my shot placement. :-)