Whiskey is sometimes spelled with and without the "e". The correct spelling would depend on the country of origin.
If it is from a country that has an "e" in the name i.e. America, it would have the "e". If it comes from a country that doesn't have an "e" in the name like Canada it does not have the "e" in the spelling.
Quick little nugget of knowledge for the day. Please share this with all of your bourbon loving friends.