I think you're correct John. I've got one of those end pins that I picked up somewhere along the way via my acquiring various instruments and parts. It tends to look a little silly seeing someone blowing into the end of their instrument to hear the note but then one has to remember that these innovations were invented long before the advent of electronic tuners as a convenience for the player. I suppose it helped having a light weight tuner that couldn't be accidentally forgotten somewhere because it was mounted on the violin. You couldn't lose it, unless you lost your entire instrument.