As has been noted MOST fighters up until WW II had cowl guns or guns mounted on/in the fuselage sides, for the US this includes ALL biplane fighter since WW I, Curtiss and Boeing. The P-26, Consolidated P-30, Seversky P-35, Curtiss P-36, Early Curtiss P-40s, P-39s, P-38s with guns in the nose? Republic P-43s. First US Army fighter WITHOUT cowl guns was the P-40D/E.