Back then it was eccentric. Today it is truly out there and illegal in most places to have an authentic human skull without a permit.
Well, you can buy one from the Bone Room, or you used to be able to. The bones come from, or used to, until China put a stop to it from China. Grave yards are dug up to make room for buildings and the old bones were sold. The bones are not cheap though, I know about this because I work a cadaver dog and have bought their search and rescue package, bits and pieces mostly. If you want to buy a skull, it is very expensive.