Thanks Jeff, for the GREAT help!!!
When I was sure it´s 100% original, I rushed to purchase the beauty...
Here are some photos:

The most beautiful are the "electric blue" hands, the seller told me that this color is achieved by putting the s/s hands inside an oven at 900 degrees (C). Not sure about that but they´re really nice!
I´m amazed by the smooth and precise working of the mechanism, it´s incredible for such an old watch to remain at that great shape after all those years...
Changing the subject:
Why do all those vintage (30, 40, 50´s) chronos have movents that are much more reliable than the large majority of todays mechanical chronos (Valjoux 77XX, Omega, Seiko, etc...)???
I see all the time some Speedmasters and other famous brands chronos that have chronicle and hard to fix malfunctions, but I never had a difficult problem with a Landeron, Venus or early Valjoux!
Of course, I´m speaking in both cases about watches that are in a good "visual" condition...
Nice week for everyone!