Correct me if I am wrong but does the term "gilt" not refer to gold?
So, the exact definition gilt is the past tense of gild and describes a specific technique of applying gold foil or leaf to certain surfaces like painted wood or metal.
With regard to watches, the term is a little more broad and is used to describe the application of any precious metal (usually gold or silver) to watch dials.
Perhaps a watchmaker could better explain but I think I've got it 😀
In recognition of Remembrance Day in the Commonwealth and Veterans Day in the US, I went with the Marathon MSAR. Respect to all those that have served.