Very nice specimen with Richards' patent top fastener. The proof marks indicate that there should be a degree of choke so if the barrels show choke present, they are original and if cylinder, they have either been shortened or bored out. Anyway. hopefully Chris Caine at W.Richards should be able to answer your question. I would think that he would be interested in viewing the photos. If you ask him he might send you a copy of their patent specifications; if not then let me know as I have a copy somewhere. Lagopus.....