This term was used by music industry.
Audio LP record master was created by cutting machine which inscribes sound groove on soft wax or lacquer disk. This disk has "yellowish" tint of lacquer. So it is called "gold" disk.
Recoding company produces this gold disk and send it to record pressing factory for mass production.
So go "gold" means the master disk is sent to manufacturing factory for mass production.
In pressing factory, the gold disk is electro-plated with nickel-copper alloy. (lacquer is not electically conductive so copper /silver is plated frist in vaccum ) This produces metalic disk with negative groove. It is called "siver disk" from its metalic color.
This metalic siver disk may be used to produce actual black vinyl disk by moding vinyle material on it.
But for mass production ( the silver disk wears out while pressing many vinyl disk), a "stamper" is created from the "silver" disk and the stamper is used for actual molding process( or pressing as is called by the music industry ).