Charleston slave badge from 1847 for Porter No. 3 named "Boy Sam"

This is a square metal slave badge with clipped corners. On the recto is text that reads” CHARLESTON [stamped]” across the top. Under that is “1847 [stamped] / PORTER [stamped] / 3 [punched].” There is a hole punched at the center top. The wearer of the badge has been identified as "Boy Sam."