As luck would have it, Frederick Douglass already is covered in the curriculum (SS.68.AA.2.8), whereas the subject under discussion (SS.68.AA.2.3) is under the description "Examine the various duties and trades performed by slaves (e.g., agricultural work, painting, carpentry, tailoring, domestic service, blacksmithing, transportation).".Frederick Douglas[sic].
I read up on Frederick Douglass' Wikipedia article. Apparently he learnt how to read despite his slaveholder's wishes, arguing that that might make him want to be free. If his duties did not require him to read it does not fall under the heading of duties performed in slavery, so he would not be an example.