Well Ralf, you may be in luck.
A recent inventory of my cams shows that I have one orphan #1 cam with the same punch mark as yours, on a bearing shaft.
If I recall the profile is more "ice cube" shaped, though it was a while ago when I last checked. I'll try and get some pictures for you tonight.
I have seen other cams with this same punch mark on the lobes - no idea who made them though.