The issue of Charleston County Parks having signage and information on their website prohibiting the legal carry of firearms has been an issue that South Carolina Carry has been addressing for several months. Senator Shane Martin requested an opinion from the South Carolina Attorney General's Office on the matter. Although the AG's office issued an opinion on this in July, and a copy was sent to the Charleston County Park & Recreation Commission, the signage and verbiage on their website still remain. Senator Martin is assisting on getting this resolved.
You can read the Attorney General's opinion at this link.