Also, among the first to acknowledge Christ were the “Magi” (i.e. Zoroastrians) because the prophesies were in there religion true. That does not mean they had a true faith, but that God laid the groundwork for his greatest revelation, his glorious Son.
Yes - in the Garden when Adam and Eve were banished because they disobeyed God, God showed us signs of the coming Christ/Savior when He covered them with the skin of an animal that He killed. It was the shed blood - a symbol of what was needed to cover us! Up to that time - Adam and Eve were spirit beings and did not need a covering. But, when they disobeyed God, their spirits died and they became flesh people. Thus, the necessity of a covering. And the preview of the necessity of a spiritual covering - one Who could bring our spirits back to life.
So back in the begining God was giving us signs in every culture of the truth of His purposes and His way.