Spotting gilding and plating
A thin skin of gold or silver.
Fire (mercury) gilding leaves a soft, slightly rich, matte gold film that wears to show the base metal on high points; look there first. It was the standard method from antiquity until the nineteenth century.
Electroplating, from the 1840s, gives a very even, bright, thin coating — so an electroplated surface on a supposedly earlier object is a dating tell in itself. Worn edges revealing a different metal beneath are the clearest sign of any plating.
Silver-gilt (gold over silver) is common in fine metalwork and shows grey-black silver tarnish, not green, where the gold has thinned.
Traces of gilding in protected recesses, with wear on raised areas, is the natural pattern — the reverse suggests a modern applied finish. Record where the gold survives; that map is evidence.