I'm assuming the S&W patents had expired, but this almost an exact duplicate of theS2W 38 DA. Some very minor differences. Apparently Marlin improved the ejection system. I can't tell what they did because the added screw is so buggered up I haven't been able to remove it. Also, the cylinder stop is not dropped by the rear sear leg. It appears to be actuated by the trigger. So the function of the Marlin is slightly different in half cock. In half cock the S&W's cylinder will free spin while the Marlin remains locked.
The Marlin is marked as patented in 1887 and I can only assume that the revised ejection system is what was patented in 1887. Because the rest of the revolver, save the cylinder stop, is a near duplicate of what S&W produced. I've seen a You Tube kf a guy that says he installed all of the S&W parts in a Marlin and it functioned.
Just got this one today and like one of my SW 38 DA's, it can be pushed off if I push hard enough. Top latch is vert tight and a decent bore.
On Monday I'll receive another Marlin. That one is almost a duplicate of the S&W Model 1 22 Tip Up. Marlin did change the cylinder stop to be mounted on the bottom of the frame instead of a hammer actuated cylinder stop on top of the frame that SW used.