There isn't a "correct" way to incorrectly render the interrobang as 2 separate characters. The name was never supposed to suggest a certain ordering instead of just being both at the same time. The name "interrobang" just sounded better than "exclamaquest" (or any of the alternatives Type Talks readers submitted).

Huh, interesting. I retract my previous statement! I'd love to read about this if you have a source.