I've seen ghosts, but I don't believe in them, so it's okay.
I've been surprisingly unlucky in that regard in my trips to Gettysburg, though, and I even took a ghost tour. Nice stories, but no ghosts. I did, however, once have an experience in a hotel that I thought was weird and I couldn't find an explanation for. I didn't consider it to be a ghost, but the next day I picked up one of the "Gettysburg Ghosts" books and found a story identical to what I experienced--accompanied by a picture of the hotel where I stayed!
I will say that Gettysburg always gives me a creepy, step-into-the-past feeling. Knowing what happened there, it's bound to. It feels like more, but those are just feelings....