A connection between RRC 363/1 and a gem in the BM has long been known. There also has been much written on the connection between these images and the statue in the forum of Marsyas and Marsyas’ status as a symbol of libertas.
I was hoping I’d found another instance of the same intaglio type.
But I think it most likely that this is just a positive imprint of the BM specimen. Ah well. The photos aren’t clear enough to be certain, but that is my hunch.