Well, as it is nearing Halloween, and I just happened to finish this terrain piece (spending only a few minutes on it at a time, usually having only a couple of minutes between other more important activities) I thought I would put the fictional battle on hold [still on the table mind you] and present this piece.
I do not know the manufacturer of the tombstones but they were of metal and I do remember primering them way back in the summer! There is very little to no information on the size or look of the cemetery; whether indeed it had wood or stone fences or indeed any at all. An illustration in Lossing's book has it overgrown but that was half a century later so really no help there.
However, battle histories do not indicate it was a fortress or indeed much of an impediment and so I did not want an indication of high walls or fences for players/troops to fight over. Thus, I used some 15mm resin stone walls to give it a perimeter but no defensive capabilities. Again having no historical basis to abide to I simply used a scrap piece of hardboard (1/8" thickness as are all my bases) which I thought might do the trick.