The 1959 NEC required receptacles to be grounding type and grounded in the following locations:
...laundry rooms, open porches, breezeways, basements, cellars, work shops, garages, on the exterior surfaces of outside walls or in like locations where the outlet may supply equipment used by persons standing on the ground or on grounded conductive materials.
Also, an outlet installed near the kitchen sink was required to be of the grounding type. (This no doubt was intended to serve the portable roll-away dishwashers that were popular at the time.)
Dawg, it seems like your grandfather's house was built before that jurisdiction adopted the 1962 NEC.
Incidentally, no receptacles were then required in the garage or anywhere outdoors, so these were strictly optional. A "code-minimum" house in 1959 would have had exactly two grounding receptacles.
