I think you're correct, even though the base has a lot of wear, I can't think of what else it could say ....
I'm not familiar with this model, but it must be dating from the late 60ies, early 70ies.
The only thing I have found so far, is a drawing of a design to be engraved on a vase, designed by Léon Halet . This has got nothing in common with your vase, except that the shape of the vase on the drawing is exactly the same, but unfortunately no name or date.
I can't post an image of the drawing due to copyright, but just in case you do have the book, it can be found in the book 'Le Val Saint Lambert' by Joseph Philippe, page 298.
They did some whacky stuff in the 60/70's, very different from what you would expect from VSL and not to everybody's taste .... but that is personal of course.