I agree with AU, either 55 or 58 in terms of wear. There should be lots of original luster visible between the letters of the legend, the date numerals, and the obverse stars. As you tilt the coin under a light you should be able to see a decent "cartwheel" effect in these protected areas.
If such luster is present you got a good deal. If however the luster is very dull or absent that indicates the coin has been extensively dipped, a process that will strip luster if overdone. If that is the case you got a nice coin but not such a good deal IMO.