Mintmarks were moved to the obverse of the nickel , dime , quarter , and half dollar in 1968 .
Mintmarks were have appeared on the obverse of the dollar coin since its re-introduction in 1971 .
Mintmarks were moved to the obverse of the nickel , dime , quarter , and half dollar in 1968 , and have appeared on the obverse of the dollar coin since its re-introduction in 1971 .