There are certainly a good number of fakes out there, but this one not only looks right, it has a pretty great provenance. I know someone here owns a set of the grips that were once on those, so I kind of hope they go to the same person, as they would more than double the value of both. Still they might not get what they are looking for for these in the condition they are in, and the provenance does not cover their actual on set usage, just what they were made for. They could easily have been a failed attempt at making a stunt, and acquired through dumpster diving. We need someone to say how many of these versions were made for filming, and a direct story to their use on the film for them to get top dollar.
Andy