Trying To Determine Year of Bell's Extra Special
 

I came across a case of Bell's Extra Special which I would guess is from the 1970's or 80's. I can't possibly start drinking this delicious beverage without knowing the age or if it has any value (I love whiskey but I also have bills to pay).

I have searched the forums for similar posts but I can only find 70 proof bottles, mine are all 86 proof. The label and bottom of bottom identify Perth. I can post pictures if that'd be helpful.