Hi Pateking,
Thanks for posting these images of the 3697 Regulator. A nice watch face, although the movement architecture and finish doesn't provide much excitment, at least in the pictures I have seen.
You will probably realise that we like to keep the focus of discussion here on the watches rather than market value, although, of course, this is an important part of our 'hobby".
When I am trying to answer these questions myself I usually start with a search of the well known auction houses: Antiquorum, Christies, Bonhams etc. There is also a wealth of information to be found in the archives here, so try the search function for more information. Finally, knowledgeable Purists may be able to send you information by PM.
Enjoy wearing this nice Breguet.
Regards
Andrew