I'm having a little trouble figuring this one out. They are calling this one a Mule which is when 2 dies that aren't supposed to be used together get used together... I guess I'm not seeing it on this coin... did an UNC die accidentally get prepared to strike proofs?? does anyone know what makes this one a mule?
Not 100% positive, but they changed the lettering on the obverse in 1991. Yours has the old style lettering on "ONZA" AND "PLATA PURA".
I don't see it as a mule. Yes they did revised the lettering style in 1991, but they made bullion Onzas with both styles and the date is on that side so it had to be an intentional change over. They made proofs with the revised style, this is simply a proof with the older style. The 494.5 mule simply looks to me like a proof 1991 494.2 The only way it would be a mule would be if they did not intend to make any proofs with the older style. That seems unlikely since the mintage for both types is the same.
