There really isn’t a whole lot of info until the V5. Even Vandoren doesn’t know. At some point, I believe that there was a relationship between Riffault and Vandoren. I’ve seen too many old Vandorens and Riffaults that are identical and you’d have to be blind not to see it.Here's a link with some old ads for Vandoren Mouthpieces - the Perfecta, Tonal Focus, and S Special: https://nicolastrefeil.com/vandoren-mouthpieces-museum
I used to have one that I think was very similar to yours that I actually sold to my teacher in high school - it was in a case with an old horn I got, and he tried it and liked it so much that he offered me $100 and a free lesson on the spot. I was fine with that since I liked my Meyer more but I'm curious now what it was.