What's should be the price?

Good afternoon,
I have a VACHERON CONSTANTIN Ultrafine model (I guess since it is less than 1.5mm thin), all 18k yellow gold, alligator leather strap.
All catalogues I had seen does not show that model, acquired for my father in decade of 1970 from a very rich man.
He said in that occasion it was am exclusive model (so I believe in it now since I had seen HUNDREDS of V&C watches).

Could someone help me to estimate the correct value for sell? 
Thank you all very much in advance.
You may utilize also my personal email: david.svaiter@gmail.com

Follow some photos:

What's should be the price?
Re: What's should be the price?
04/12/2013 - 02:49
Hello David and welcome, We do not discuss prices on this forum. For such an estimat, you should go to an auction house such as Christies, Sothebys, Antiquorum. Nevertheless, the model looks like a "disco volante"  and is close to a Ref. 4786 if 35mm wide, with the Clous de Paris guilloche bezel and the 9-ligne caliber 466 "pitch-fork" movement. Horological regards, Berny
Re: What's should be the price?
04/15/2013 - 16:47
I can't give an exact number on here, but let's just say, probably not as much as you are hoping.