There is no useful reason to put a heat shield on a shotgun. Some people think they look cool but they serve no practical purpose.
are heat shields "those shoulder mounted folding things"
they really do serve no purpose unless your planning on firing hundreds of rounds per range trip..and even then they dont make that much of a difference. some people think they look cool...I guess.
No, they are metal or plastic covers for the barrel that are supposed to keep you from burning your hands on the hot barrel. Just google shotgun heat shield and go to images.