The gold tint IMHO is an affect of age and or a thin coat of the top "plating" Remember that allot of NOS parts available now and for a number of decades are ones that others passed over in the past and were just tossed back on the shelf. On many of these the base material is an off white yellow colored product so its possibly starting to wear or show through
It was not unusual for many of us to go to Ford in the 80's and go through a dozen or more of just about any part - pick out a nice one and leave the damaged, box worn, defected or ones with other issues. Sometimes there is a reason why the parts are still in the box rather than on a car.