You may or may not find any Japanese markings on it. I own a NM3 that letters as shipped to Takata & Co. in 1891 that has no Japanese markings of any sort. It is nickel with hard rubber grips and letters as such. It also has the lanyard ring on the butt. I do not know the history on my pistol, but can only assume it would be somewhat similar to yours. You are very lucky to have that history to accompany the pistol. Please document that history and keep it with the pistol.