Large Scale Boucher Gold Plated Porcelain Courting Couple Miniature Transfer Brooch

This brooch is large (3" x 2") and weighs 51 grams. Features a cenral oval shaped porcelain plaque with what appears to be a "transfer" painted courting couple minuature signed "Boucher" in script at the bottom. Ornate gold plated open-metalwork frame with a silver colored base metal. I tested the base metal using acids and a touchstore, and the streak did not change when exposed to 14k and Platinum acids. However; I tested another vintage "pot metal" piece and obtained similar results, which is very strange...Anyways, the finding is a one-piece saftey pin that was applied to the backside. I cannot tell if it is original to the piece. This style of pin was patented in the 1940's, I believe. There are no hallmarks whatsoever on the metal, and the only identifiable marking is the Boucher script on the poreclain plaque. The painting appears to be reminiscent of Francios Boucher, which leads me to belive this piece was not created by Marcel Boucher, the well-known Vintage jewelry designer. This piece is in excellent condition - only a approx 1mm sized area on the side of the pin where the plating has worn away. I would appreciate some feedback on this piece, as I have been researching it for a long time and just cannot seem to identify the date of manufacure, material composotion or designer. I would like to list this piece for sale in my Ebay store (Nikki's Estate Jewelry Boutique), but I do not feel comfortable selling items that I am unable to authenticate, and I cannot seem to figure this mystery out on my own. Thanks so much!