Is this the beginning of a vow turned in Bodhisatta?

I was reading this from Elder Tissa-Metteyya. In later tradition there is these names used each alone for a Bodhisatta.Mainly in the later tradition. But then it seemed to me, this is the root story, but it seems really brahmanic. Even the former Buddha prediction.

But still the prediction is that he will become Arahant. So later it was turned into another prediction?