A balance will show the same reading for an object even if you go to the moon.
$$W=mg$$
Where $g$ is the planetary body gravitational acceleration constant at which you are taking the measurement. A balance will correctly show the same mass of the object interdependent of where you are the moon or the Earth. Using a spring scale on the moon will report the gold to weight about 1/6th of the weight on Earth.
Balance measures invariant rest mass m, scales measure weight which gravitational acceleration $g=9.81 m/s^2$ varies on Earth per latitude due to centrifugal forces effectively (Earth's spin) changing $g$.
So, due to spin of the Earth and centrifugal forces created, the weight of an object can vary between the poles and Equator of the Earth depending latitude position up to 0.3%. Actually, at the Equator the Earth spins at about $1600 Km/h$ and an object there will weight about -0.3% less than at the poles due to the spin of the Earth. Usually this is not a problem but for a relative large quantity of gold this can make quite a lot of difference in money value.
Finally, calibration weights for a scale don't solve the problem since they are subject of the same centrifugal forces. Unless, the digital scale is not programmed to input latitude position or have another way to compensate they will have always this drawback.