Ishallperish,
Gold and silver are weighed in troy ounces, which different to the avoirdupois ounces that are normally used for weight and measures.
1 troy ounce is 31.1grams, (1000/31.1 = 32.1 ounces in kilo of silver)
avoirdupois ounce is 28.35 grams.. I think this is where you got the number...