The belly of a golden is Ivory with a grey undercoat and looks greyish usually as the fur is so short. The way to distinguish between yellow and golden is to look at the undercoat. The golden will have a dark slate grey undercoat where as Yellows have an Ivory yellow undercoat. The exhibition standards are here but remember these are for the 'perfect' hamster and no hamster is perfect in every area!
If she does have 'yellow' patches she could be a Golden tort so check all the areas for undercoat and see if any have yellow roots with other areas showing grey roots. The shorter the hair area the less undercoat you see which is why faces often look paler
https://hamsters-uk.org/syrian-exhibition-standards/