Yes, sharpshooters are not necessarily snipers. There are four classes of sharpshooters from blind squirrels who find themselves in a designated sharpshooter unit up to the men who carry specialized rifles and are capable of hitting their mark at long range. This is discussed in the introduction to "Sharpshooting at Gettysburg" that appeared in Issue #39 of The Gettysburg Magazine. There were independent sharpshooters who did serve as snipers and this is discussed in the article on Confederate Sharpshooter Selection that appeared in the Summer 2009 issue of The Military Collector and Historian. More extensive discussion may be found in Chapter 7.

Concerning the black man, you are probably thinking of Holt Collier. However, no evidence has been found that proves with certainty that his marksmanship was superior to any other Southern sharpshooter or even any Yankee sharpshooter. Research has revealed that no nation or group holds a monopoly on marksmanship or sharpshooting ability. Used here, sharpshooter, means a military marksman and not just an infantryman who has that title. Returning to Holt Collier, he is discussed briefly in the article, The Black Confederate Sharpshooter, that appeared in the Summer 2007 issue of The Military Collector and Historian. Collier is also mentioned in Chapter 8. That Collier was good doesn't mean that others didn't make more amazing shots. Even if someone did hit his mark, the question to ask is what is the probability of doing it again? The degree of consistency or number of hits determines how good a marksman a sharpshooter really is.