When I did Confederate Reenacting in the early through later 80's, we were not allowed to reenact on most of the actual battlefields except New Market and Cedar Mountain, though we were in the operational area when we did the 1st or 2nd Battles of Manassas.
We were allowed to reenact Pickett's Charge at Gettysburg one time during Remembrance Day at Gettysburg, but there were no Union reenactors. Still it was an extremely emotional moment.
Some of our guys would go to Gettysburg during the Labor Day weekend every year and we would wear our Confederate Uniforms on at least one day. Got a Daguerrotype of us in uniform from one of those trips. We normally toured the battlefield in "civilian clothes," though.
One time when we were in an area that Ohio troops fought in, one of our guys just happned to kick up an original Enlisted Man's US belt plate. That was sort of neat, but it also had a soldier's name and unit carved in the lead in back of the plate. There was no way this was a reproduction as you just can't fake the amount of oxidation that was on the brass and lead parts. Anyway, when he researched the guy, turns out the original soldier was an Ohio Soldier who won a Medal of Honor as a Color Bearer, in that area of the battlefield . I suggested he donate the belt buckle to the museum and he later did that, though he hung onto it for a couple of years.
Three things on original Minie Balls.
First, the South could and did use captured .58 caliber paper cartidges for the Springfield in the South's Enfields as the ball sizes were .575" maximum and they fit in the .577 cal. Enfields.
Second, Confederates also used Smooth Minie Balls and even a smooth ball for the .450 Caliber Whitworth rifle when they did not have the octagonal bullet molds for them.
http://sgtriker.com/bullets.htm
Third, Buck and Ball rounds were used by even the North FAR later than most people expect. At Gettysburg, the 12th New Jersey used .69 caliber muskets with that load and even made a monument with the buck and ball load on top. Here's the link:
http://www.gettysburg.stonesentinels.com/NJ/12NJ.php
There were battles in what was then called "The West" that is actually what we call the Midwest today where late in the war (1864) Northern troops dropped their .69 caliber smooth bore muskets and picked up Enfield Rifle Muskets off the wounded or dead Confederates. I don't have a link handy for that, but I have that somewhere in my books on the war.