graculus

It's not specifically stated that he's A, but there are enough clues for the people in the tiny fandom to pick up on, but also to understand why he'd think he was B - in the show (Wild Wild West), A's picture has been put up on wanted posters that say he's B, so when he gets amnesia and finds one of those posters, he thinks he's B once he sees that's his face on the poster. So actually, A is B, at least physically. Even more confused now? ;)

And thanks for the vote of confidence. :)