I don't intend to sound nasty, but you can forget about VSL....
Two different concepts, materials and techniques...
The galvanoplastie technique was indeed a concept designed by Ledru but usually the whole item was galvanized in copper on a layer of silver, with just a few exceptions and was done between 1910 and 1922/1923. The early, unmarked items were done under commission by Ledru, at the SA 'Le Métallisation' in Lille, France because VSL didn't have a workshop yet installed at VSL. This was done in 1918 and the production lasted only for 5/6 years.
The mentioned vase 'Cortège' has got a different technique and is part of the early 'Danse de Flore' series, for which 24 Ct gold was used. Note that only the subjects/persons are covered with gold, not part of the bottle or vase like this atomizer.
So basically, for the galvanoplastie technique copper was used and gold on the Danse de Flore, like the vase Cortège and the blue box in the link.
The 'Améthyste' series from VSL that looks like this atomizer was done from 1926 until 1937, but the difference is that it was double cased from the inside out and that's missing here.