Help Identifying Civil War Gun

This civil war era gun has been in my family since my 3x great grandfather carried it during the war. It’s hard to see especially in pictures but it was gold engravings all over it. I would love to know what gun it is. It’s got 2 triggers and 2 barrels. that is really all I know about it. I hope to get it restored and even functional if it all possible. Any help on identifying or facts/history about this gun would be very appreciated!