In order to stop supplies from reaching the Union army, and to get supplies for themselves, the Confederate navy attacked and captured ships at sea. While technically known as "privateers," the only difference between a pirate and a privateer is the spelling.
This man was a very passionate student of history. Some of his gear was original from the American Civil War; perhaps he was, too.
The explanation for the upside-down belt buckle? Many of the Confederate soldiers were enlisted in the regular army when the war began. When they enlisted with the Confederate Army they took all of their gear with them.