Hi Fabio,
I don't know the reference number, but there is a skeletonized version of the 3757 that is absolutely sensational (and I don't even care for the 3757 that much!). I'm a big fan of Breguet and love many of their watches, but when I saw the skeletonized perpetual tourbillon in platinum, my jaw dropped wide open. I've seen a lot of fine looking watches in my short time in watch geekdom but this piece is truly something special. Definitely check it out before you make your decision.
_john