I wish you hadn't been so over-courteous about putting the inscription on a card instead of on the flyleaf. It's the bookseller coming out in you all, you were afraid you'd decrease its value. You would have increased it for the present owner. (And possibly for the future owner. I love inscriptions on flyleaves and notes in margins, I like the comradely sense of turning pages someone else turned, and reading passages someone long gone has called my attention to.)