Like you I´m also very curios about the origin of this weight.
First I thought it could be a Clichy, as I saw some roses without petals in the 2005 and 1991 PCA Bulletin, but then I thought more it could be a Val. St. Lambert, but was irritaded about the torsades on the side, which have the french national colors.
Probably you are right with St. Mande as the “tadpole” really looks very similar from this view of the weight, but probably it is a portrait or a silhouette from St. Louis.
Another mystery is the cane with the 5 red dots on the right side of the weight. I saw this cane some months ago in another antique weight, but I have forgotten where.
Tomorrow evening we all knew more. I hope the traffic is not to terrific as I travel to Bruxxels to pick up the 4 weights.
Have all a very nice evening.