I'm not at all familiar with 164s, but if the gizmo in your first picture were in a FI 140, and it were a fuel vapor trap, there would be two hoses coming out of it. One would go into the intake manifold at the forward end just below the throtle position sensor, and the other would go back to fuel tank, or its venting system. The thing you show, however, appears to have a T connection on top with some sort of valve in one arm, to which a hose is connected. So it could be that the T does the job that the two separate hoses in the 140s do. In which case the second holecould just be a vent -- the cannister in my "71 142 is open at the bottom, with a filter in it.
Bob S.