I had always thought that this was the ROTJ Vader stunt prior to the other detail elements being added. If so, it appears that it never had a GRAFLEX clamp to take from.
Regarding the rivets not lining up in the bladed ESB stunt example I posted against the holes in the clamp of the current V3 clamp, that was meant only as an example of a bladed ESB stunt to illistrate a theory. These things were far from uniform in their execution. It’s entirely possible the V3 replacement clamp was pulled from a GRAFLEX bladed stunt with only 3 rivets or screws in the clamp.