America definitely loves comics and superheroes. He has actually dressed up as Batman in canon. (And he suckered England into being Robin.) I've generally been approaching these sort of situations where he notices that the character he's face to face with is similar to something from back home, but he doesn't actually fourth wall them. (ie when he met one of the Tranformers he went "ooh a real tranforming robot alien just like from the movies" not "you're a character from the movies back home") So Robin will be "a real costumed crime fighter like from the comics I read back home."