I have a feeling Claire put a bit more thought into her gift. Marten was just like "Oh hey Claire likes books I bet she'll like Jane Austen yeah that's good enough."
Regarding Claire, I think that it reopens the debate as to whether she's a bibliophile. Additionally, that isn't a
modern hardcover. The way it looks makes me think that it could be quite an old printing with its own intrinsic value. There
is a message though - It's the story of a lonely, virginal but tough young woman who met Mr Perfect, even though neither of them knew it at first. It's also about the minefield of social prejudices that stood between them and 'happily ever after'.
Foreshadowing? Possibly.
In any case, it's nice that they both got the other something in line with their interests but also reflects the value that they place on eachother.