For an 1872 engraving of the campus, try this
http://en.wikipedia.org/wiki/Old_Campus_District%2C_University_South_Carolina

Lieber College is the first building to the right of the Horseshoe. Rutledge Chapel is the building at the top of the Horseshoe with the dome. South Carolinians Library is the first building on the left of the Horseshoe.

Longstreet Theater is the tall building at the bottom left center of the engraving. It seems to me that the Nitre Bureau occupied one of the buildings on the campus. To my knowledge, the only building on the Horseshoe which is not there now is the building at the top of the semi-circular drive; it was razed and a new Library built there in the 1930's. I am of the impression that the Honors College occupies a good many of these buildings today, including some as dormitory space for Honors College students, axactly the use they were devoted to when built.