Some countries require certain copyright formalities5 to establishing copyright, others recognize copyright in any completed work, without a formal registration.
Agent Carter seemed to like Steve's innocence before the serum, so when he came out looking like an adonis, she was head over heels for America's hero.
His position at Red Skull's side and his knowledge of their futuristic technology made him a valuable asset to the Americans once he was captured by the Howling Commandos.