Depends on who it is. The actor who played Third Remata'klan in "Rocks and Shoals" is the same person who played the African American cadet who appears on the bridge of the Enterprise
in TSFS. Had I not looked up Remata'klan's information on Memory Alpha
, I'd never have guessed they were the same actor.
Edit: The actor is Phil Morris, who's probably best known for playing Jackie Chiles on Seinfeld