The 441 might be a post war arsenal marking, probably had nothing to do with the war. The date on the lockplate, should match the one on the barrel. Like others mentioned, without specific markings, you'd just have to be happy with knowledge that the gun was made during the civil war, and possibly used in that war. Some of these muskets show up in such good condition, you have to question if they were ever issued. Either way, nice example.