Several years back my son a friend and I were hunting elk and I found a freshly busted off 5th and 6th point elk horn. It was might big and as we were sneaking in towards the elk we could hear them fighting. That happened to be about 2 o clock in the afternoon. And just before dark that evening, some mile or two away from where I found the antler (which by the way I picked up and packed out) we saw the bull come by us, but he was too far to shoot. But you could see the break and tell it was definitely the same bull. It would have been neat to have been able to arrow that bull. It would have make for quite the story.
But that didn't happen, but I hope you can find the broken part of your moose antler.
On a side note, some years back, I was sitting a treestand and several of us who sat that area had seen a nice bull moose there several times (we had no moose permit) and then one night a buddy sat and told me he had come back in but one side was busted off before the brow tines. A few evenings after that I sat the stand and had him come in and he came over to the base of the tree where I was sitting and began to rake his antler on a piece of bush at the base of the tree. I could look straight down the tree and watch him. I noticed he raked the side that he still had, but then would turn his head and rake the side he didn't have, as if he didn't even realize it was gone.
Anyway good luck to finding the final piece to your puzzle!
Have a good one. BB