OK, here's from someone who occasionally works in the mail room at my place of employment. First of all, the envelope generally gets tossed. The HR person is not an officer, and she may or may not look at a CV or resume right away - it is given to a secretary and filed somewhere unless there is an active search for new personnel at that time.
I also play receptionist for a short time each day, and when we get questions about HR we tell the name of the correct person - spell it - give the address - whatever it takes. My guess is that the HR person likes being addressed by her name better that Sir/Madam, but if the CV looked good it probably wouldn't matter too much. But, that's one job I don't get to do - they NEVER ask me about hiring or firing (and I have big opinions about it, too!).

What sane person could live in this world and not be crazy? -Ursula K. Le Guin, author (1929- )