Ron;
Thanks for the info. I do not recall mine have the rounded hinge pin ends, just flush with the frame. It did have the removable bottom plate, & had push rods for cocking with forend iron cams. May have been the 325. I once had a 20 ga model 315 though marked Central Arms Co, totally different type action. I don't recall at this point in time if my first one had a patent date marked or not.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra