Mark;
I do not know if it is a rebounding or not, but viewing the 4th gun photo from the top of the article (the photo with Hendrik Fruhauf's name) I am impressed at what a beautiful lock it is and the superb craftsmanship. Also look how beautiful the color case hardening is. Of course, the Germans have always been at the top of the engineering disciplines.
Further in regard to your thoughts on if it is a rebounding lock, you will notice in this photo that the bottom of the tumbler is 2 mm away from touching the bridle---causing one to consider such.
