Yes you are breaking the law. The only exception to this is:SECTION 16-23-420. Carrying or displaying firearms in public buildings or areas adjacent thereto.
(A) It is unlawful for a person to possess a firearm of any kind on any premises or property owned, operated, or controlled by a private or public school, college, university, technical college, other post-secondary institution, or in any publicly-owned building, without the express permission of the authorities in charge of the premises or property.
It would not be a violation on 16-23-430 but would be a violation of 16-23-420.(E) For purposes of this section, the terms "premises" and "property" do not include state or locally owned or maintained roads, streets, or rights-of-way of them, running through or adjacent to premises or property owned, operated, or controlled by a private or public school, college, university, technical college, or other post-secondary institution, which are open full time to public vehicular traffic.