Barry, it looks like Victrix may well have split the rules into infantry, artillery and cavalry sections, possibly intending that each rule module would appear with the appropriate figures box, though they didn’t get around to doing cavalry. The Perry’s did similar for their original ACW.
The Victrix web page has the infantry rules and a separate download for artillery, so it looks like the cavalry rules never made it to the site.
For whatever reason, the Sharpshooters rule did not make it into their infantry rules ..... perhaps because the rules were being packed into boxes that didn’t have such characters.
Anyway, for the benefit of enquiring minds here, the Sharpshooter rule that you sent me is as follows;
SHARPSHOOTER: A picked marksman who fires only aimed shots at specific targets. If a unit has a Sharpshooter it throws a single separate shooting dice during any shooting activation. Before the dice is thrown the shooter names his target which can be a specific character model in an enemy unit. On a score of 6 which is totally unmodified for any conditions, terrain or cover at any range, the enemy character is dead! The target need not be in the same unit at which the rest of the sharpshooter’s parent unit is shooting. Sharpshooters all shoot as if they have a rifle. Only one Sharpshooter is allowed in the army.