Gang,
I think these narrow feeler guages may have been designed for small engine service (think motorcycle, lawn mower, boat motor, chain saw, etc). The points in these engines are typically very small and located inside the magnito/flywheel assembly. To set the point gap or the timing, you generally have to work thru a small window in the magnito/flywheel. This is where a narrow feeler guage would be a real advantage. I could be wrong though...
But, check out these photos of an RK ignition kit wrench from a 1960's vintage 2-stroke motor cycle:
Note the narrow (about 3/16" wide) feeler guage used for setting the points inside the flywheel. Look familier?