Hi David/katana. Please forgive my habit of being sometimes over-critisize, I can't help it as research is part of my daily wages.
If you check my photos from the fencing collection you will find at least one pair of sharp duelling foils - especially those with colonial-looking cup hilts, so I don't have problems with the thought that your foil was indeed for duelling.
Great innovative "macro shots"
! As I can see now there is a small recess between the guard and the shoulders, your foil may bee missing a thick stiff leather washer that used to cover the entire 8 figure guard, thus closing the large holes and protecting the hand.