Cleburne implemented a division-level corps of sharpshooters (the best shots from his division), however the rest of the men under his command were no better trained than any other. In the latter half of the war you did see sharpshooter battalions formed in every brigade in the Army of Northern Virginia which, for the most part, trained in marksmanship, range estimation, etc., and essentially fought as 'elite skirmishers'. That was also the case with Berdan's U.S. Sharpshooters and other sharpshooter contingents.Per Saphroneth: A division that learned to shoot, had a huge advantage. Didn't Pat Cleburne teach European rifle usage?
Though even with troops properly trained in marksmanship you still have to account for the black powder smoke, terrain, combat experience, etc. With the exception of sharpshooters and skirmishers, I don't think 19th century warfare often allowed for carefully aimed shooting. That wasn't really the case until the implementation of smokeless powder and more open order tactics.