Hi there!
I have tried to find an answer on that topic myself but unfortunately I did not.
So yesterday I did spent some time to farm some things in Craglorn and went into a delve too. I was a bit surprised that the bosses within the delve did have the same drops like overland world bosses (head, chest, legs, weapons from sets). Now that was somehow strange for me as it shouldnt be like this, at least it isnt within other zones.
This leads me to the question if this is intended or if this is a bug? Might be that for Craglorn its different - never really paid attention to it, so I am just curious.
Thank you!