Yes, both are required. You need to get yourself a lake map and see where the boarders are located. You will see that above Buster Boyd bridge on the left side up to Catawba Creek bridge is in SC, with the state line crossing in front of the bridge. Little tricky at this point. Every thing on the right side is NC. Below the BB Bridge NC is on the left side all the way to Torrance creek with the state line crossing just in front of the island. SC is all the way from BB on the right side to the dam. Yes it is a fine line with the law. Pays to know where you are fishing. Some use center of the lake as the boundary to be safe. It's not a hard lake to figure out. Good luck and welcome to the board.
DNR rides with the County cops some times, so don't get alarmed when they approach you..