Hi,
I am aware of very few examples of European guns with unprotected "ball triggers". For those unfamiliar with the Scottish version, the trigger was several parts. At it fullest development in the 18th century, the trigger ended in a rounded or squared stud over which a silver ball, often made of 2 hemispheres soldered together, was placed and the end of the stud peened over. Earlier Scottish pistols had one piece iron triggers with a lobe at the base. I am aware of a number of mid to late 17th century English pistols with ball or lobed triggers and no guards. Most were screw barrel or turn-off pistols. There are three surviving 16th century English wheellock and snaphaunce pistols with ball triggers but all had an effective safety latch on the trigger, which later pistols discarded. There are a few early European wheellocks with simple unprotected triggers but not necessarily with ball or lobe ends. I think most gunmakers everywhere realized it was a bad idea not to have a trigger guard. The Scots were just stubborn and had to be different for longer.
dave