1986 Mexico Proof 1 Onza "Libertad" 1 oz Silver KM.494.1 - NGC PF 69 UCAM KM.A623 Here is a superb specimen

Here is a superb specimen of this slightly tougher date to make in this grade

I'd put the strength of the mintmark in this case at slightly above average when compared to other "Weak D" coins

Printed with a red "R" and "S" overprint

This is the Burnished Uncirculated version of the South Dakota Mount Rushmore 5 oz silver quarter

1986 Mexico Proof 1 Onza "Libertad" 1 oz Silver KM.494.1 - NGC PF 69 UCAM KM.A623 Here is a superb specimenComposition Silver Fineness 0. 999 Weight 31. 1 g 0. 9988 oz ASW Diameter 36 mm Edge Type Plain Subject Libertad Description Obverse National arms, eagle left Description Reverse Winged Victory Mintage: 30,006