You said "I could use some info about the fuze." It is a civil war era Percussion fuze... which means it was detonated by impact. The version you found was invented by Benjamin B. Hotchkiss and originally patented by him on June 17, 1862 -- but he modified it to the form you found in an "Improvement patent" on February 24, 1863. Thus, the specific version you found has only been dug at Spring-1863-and-later sites. It is strictly yankee-made.
The disc (called the "anvil-cap") in the center of your fuze's face has a different color of patina because it is made of a different brass-alloy than the fuze's main body. As Jpro mentioned, some Hotchkiss Percussion fuze anvil-caps were marked with the inventor's name and patent dates, but yours seems to be unmarked. I said "seems" because the marking was often not stamped into the brass very clearly. See photo below, which shows a somewhat weakly-stamped marking on a non-excavated specimen of the Hotchkiss Type-2 Percussion fuze. Notice that the word "patented" is unclear and only the "1863" portion of the second patent-date is visible.
