There are so many broach molds out there. Would be hard to search so many cake selling sites to find it. Here, where I live, we have a few chain of costume jewelry stores, I would buy a broach there that best matches what’s on the cake and make my own mold with gumpaste. That’s the only thing I can suggest. As far as the original decorator…not sure how you figure that out…
Creativity is God's gift to us. Using our creativity is our gift back to God. Clarky's Cakes 😎