yes I believe that is a shell fragment . Cant tell if it is Confederate or not for sure but I have dug fragments just like it in Petersburg Va that were most likely Confederate.
Hard to tell, Roger. If you found it north of the river in Hartville, then likely yes. If you found it south, then likely Yankee. Both had artillery at that battle. And both had guns capable of lobbing 12-pdrs, which I believe your frag is.