Interesting exhibit!
There used to be a great 2 part interview with James Gawley "Jimmy Claws" about his work making the claws for the films but the link appears to be dead now.
http://krisabel.ctv.ca/blog/_archive...6/2450347.html
I have most of them saved from this interview including some shots of the claws in this exhibit-
Looks like these were made to push through a prosthetic rubber fist to get the "over extended" look.
I tried to find the interview on the internet archive as well to no luck. I think he mentions these claws in the piece.
Nick