I assume that all three "species" of deer CAN cross; I've shot muledeer/whitetail crosses in eastern WA, and blacktail/muledeer crosses in northern CA. But I never heard of a blacktail/whitetail cross, although I don't know of any reason there couldn't be one, especially in BC.
I agree that it would be a very unusual rack for a pure blacktail. In any case, GOOD JOB!
