With all due respect to BMbikerider, I must disagree with his dating estimate.
Kodachrome rolls of 18 exposures were introduced at the very beginning of the 35mm Kodachrome lifecycle, around 1936-1937.
You have in your hands, Rich, a glorious piece of photographic history.
Here is what the outside box looked like.
I hope someday that you will find an original box and complete the package.
Best of luck.