I was told years ago by a curator at the AK Museum that the bones were either resin or plaster and a couple of medical chums also put this thought forward. It may be, that with the passing of the years, the current staff aren't aware and/or haven't looked! Curious!
I do however find it utterly offensive that many Druids and Pagans wear antlers and furs ... as offensive as a fur coat and almost as debauched as displaying a dead child in a museum! That said the 'skeleton' at the AK Museum has always been treated with deep affection and indeed respect too ... I can't apply this logic to the cruel and senseless slaughter of animals.