Is there a way to tell what wall the headboard will be on?

Not a silly question at all. I have been successful in having Carnival change my bed around on 2-cruises. I let our personal planner know what side of the cabin I needed the bed and when we arrived it was already switched. On another cruise i asked the room Stewart to make the change and it was done right after the muster drill.

You do there are about a dozen variables in cabin design and shape.