I suspect that broadening the definition is better. A lot of things are variations of a Golden Deck, and don't really need specialized terminology. People would understand you fine if you called KC/KC/Explorer/Province/Bishop a 'Golden Deck', or if you called 'Plat, Plat, Bishop, Colony' a Golden Deck, and so on. And even with a province-buying golden deck, it can switch to buying golds instead of provinces, and it can be composed of different combinations of treasures or actions.
Proposed definition: Golden Deck: a deck which plays a Bishop each turn for VP chips, and immediately re-gains any card which was trashed, thus gaining points without changing deck composition. For example, the 5-card deck of 'Gold, silver, silver, Bishop, province,' trashes and buys a province for a gain of 5 points per turn.