Check out the book Fighting Grasshoppers. There's a picture in there of an L4 with a bazooka (no recoil) mounted on the wing struts on each side. Apparently the pilot had got fed up with the German ground troops taking potshots at him while doing AOP work and he wanted a method of retaliation
As somebody said a while ago, the last air combat in Europe was between an L4 Cub (the passenger had a gun) and a Fiesler Storch. The Cub won!