That makes a lot of sense. I don't think Caroline's dress was meant to be undergarments - the fabric seems too finished/satiny and dressy to be a chemise or what-have-you (displaying my ignorance, I am). But those are indeed some very illuminating paintings.

Even if it was accurate, which I think it is pretty firmly not, I think it jerks the viewer out of the story (at least it did me) and makes them think "Wow, what a modern dress."