Yes it is a civil war 1863 Sharps carbine from the distant photos. Is this still a linen cartridge gun or has it been converted to the 50-70 Government cartridge? It is easy to tell, does it have a nipple for a musket cap or a firing pin?
Then you have what is known as a model 1868. Thes guns were one of the TRUE west civilizers. After the civil war these were converted to 50-70 Gov't, then went out west to arm the calvery in the indian wars. When replaced with the "trapdoor Sprinfields" these were sold or given away to settlers, wagon drivers, buffalo hunters ect. Free ammo was avalible to individuals in the buisness of buffalo hunting.