Help with Identification

[bmbjmck]

Hello,
 I inherited a Mauser HSc from my father. It appears to have M III/? under the eagle on the left rear of the trigger guars\d. (Not a question mark but cannot make out the marking, weather it would be a number ot letter). There are "N" markings on the eagles on the other side of the trigger guard and the end of the barrel. 3 lines on the slide. Slide reads Mauser-Werke A.G. Oberndorf a.N. Model HSc KaL. 7.65 MM. Serial 909xxx
 Thank You!