Architectural sketches

I recently came across these sketches at a local thrift store. As I’m new to the Charleston area, I had hoped that the sketches were of one of the local historical buildings in downtown. After some research, I found that it was indeed my lucky day. They appear to be architectural sketches of the Exchange Building on East Bay Street. I couldn’t find anything else, except that the originals were done in 1766 by an Irish architect named William Rigby Naylor, and that mine may possibly be part of a reproduction set of 400 done in 1973. I didn’t find any numbers on them, but I also did not remove them from the frames for fear of damaging them, so I haven’t seen the backs. If anyone knows anything about them, I’d really appreciate the information.

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