This would be American or possibly Canadian, definitely not European. Whiskey is likely but could have held all sorts of things. The "Full Pint" in a slug plate is unusual, I don't remember ever seeing one like that before.
The Gould Act of 1913 required all bottles or labels of bottles to be listed with the volume the bottle would, not just could, hold. Most bottles that tell the volume of the contents date after this Act.