Considering that some of the profanity-laced grafittis on it were anti-confederacy, that is highly unlikely.
The Gettysburg battlefield is full of monuments to the southern side and none of them are vandalized that I'm aware of.
I would be surprised if there were not any at Gettysburg. Vandalism is fairly common at battlefield monuments. For example, a few years ago at Shiloh somebody vandalized Texas monument and stole the marker of the spot where Albert Sydney Johnston was shot. Considering the number of people who flow through Gettysburg, it is unlikely that it has not experienced the same.
This may come as a shock to you but the confederacy did not enjoy universal devotion from all the people living in it in the 1861-65 time period. Maybe it was one of their decendants?
I would be surprised if there were not any at Gettysburg.
All I can say is that I'm not aware of any.