I agree with Rocketman that a hidden 3rd bite would be more typical of a newer gun, rather than something 100 years old. I've seen older Francottes with Greeners (both standard and concealed) and doll's head extensions, and even owned one that had both a doll's head and a hidden Greener. If it has the hidden 3rd bite, I'd toss in my vote with those who say the entire gun is from the post-1924 period, as the proofs on the barrels indicate.