Yes, you can get Goldstone, Bars, Dust, and even Coins from looting random enemy corpses, but not many will drop them for you, even though looting is always a helpful way of getting different items while exploring the map you're playing in. It will take a longer time to get the amount of Goldstone and other gold-derived resources you exactly need through looting NPCs and even loot chests than by choosing the different ways previously mentioned in this guide, so this option is not a reliable way of obtaining gold as the main source (but always an extra help, of course).