Hang on, you macabre people - you can't count any skeletons (plastic or otherwise), as we have no idea how they met their demise; if this thread is to tally "fatal violence
", you can't make assumptions that the skeleton was provided by a death by violence - it might have been a body donated or sold to medical research.
I don't think doctors use plastic skeletons to study.
If they don't, then why do supply companies produce them? My dad (admittedly not a doctor, but a vet, who retrained as a biology teacher) taught human physiology, and his classroom skeleton was definitely a plastic one...
I agree that medical students usually have a genuine human skeleton (actually often only half a skeleton) to study, but lots of places will have plastic skeletons for demonstrations in lecture halls or classrooms, especially when many of the people involved will be non-medical staff who may be squeamish or otherwise reticent to deal with real human body parts (so in the case of the Space Centre, a plastic skeleton may be still be useful for a physiologist to show an engineer how some aspect of a design will affect a user of equipment, or wearer of a space-suit).