Since I turned this thread into a joke thread, I felt responsible, so I did a little bit of research.

It appears the item on far left is a threaded bolt with a molded handle. The item in middle appears to be more of a threaded insert so that if the thread get screwed up, it can be replaced. What's on right appears to be a friction pad that does the part of actual locking.

You MAY BE able to buy an appropriate threaded rod or screw to substitute for item on the right but isn't this all METRIC threaded? For item in the middle, both male and female thread must be right. I would think it will have to be custom made. What's on right, you could probably use a piece of rubber or plastic if you must. It'll probably be easier and possibly cheaper to purchase a factory replacement....