Yes, but what I suggest is that with the technology that caused agricultural surplus and thus money economy there arrived a greatly increased need for moral code that is founded as default upon interpersonal honesty and reliability. I think that the causal relationship between economic development and morality is not sequential but contemporaneous. Thus the moral code is natural in the sense of inevitable. The universal component of The Golden Rule is a later civilised development of the more basic honesty and reliability which suits all societies from the tribal nomad to the huge political collectives of the modern world.Prior to the invention of money economies, the most efficient way to sustainably get material goods by cooperation was by acting morally – for instance in accordance with the Golden Rule (which initiates indirect reciprocity).
Obviously, especially in view of international tensions, we are still working out the universal component of the Golden Rule.