I was looking for a small wrench 3/8" in my small box of those type wrenches and discovered this wrench.   I didn't know I had it.  I wonder how old it is.  My camera is on the fritz, but I found this photo that is just like my wrench.

perhaps a magneto wrench?

I used to have - maybe I still do - a wrench similar to that for CZ/Jawa Czech-made motorcycles, that came with two feeler blades riveted in the middle.  One, I believe, was for the plug gap; the other for the point gap.  Had it been a four-stroke motor, I'm sure they'd have riveted on a third one, for the valve clearance.