To get back to the original question about blossoms, it could very well be Reliance since the fruit characteristics match. There is something weird about plants, some of them at least, in that sometimes one branch will have different characteristics, like varigation. They are called “Sports”. I have a Dorsett Golden apple I am told is an early ripening sport of Golden Delicious. I also have a Cara Cara Navel orange (pink inside) that originated as a single branch of a navel orange tree in Venezuela. Every Cara Cara Navel orange tree in the world is the result of grafts, directly or indirectly, from that branch on that tree.
It could be that your tree originated as a graft from a ‘sport’ of Reliance. Just a thought.