Not 100% sure, but I think when you kill him in the quest line, whether it be 1 or 2 play through, he will almost always drop a legendary. I have 3 characters at 50 and he has always dropped in the quest line, but have never got a drop from him farming.
I got a Deliverence when moonshot farming. So he can still drop other things like usual, just not very often.
Interesting....... he probably keeps the same low drop rate for any oranges all the time, even when moonshotting. But, those 5 I listed are jacked up to the high rate for the moonshot. This is good stuff....informative.