First post (but I've been lurking for years, and am also a member of other prop forums, such as Rebelscum, ASAP, and The Trek Prop Zone).... Greetings.
Anyway...
While this Elstree saber certainly is a cool item, I don't necessarily think this is a real prop made for the film back in 1982.
Consider this:
Various sources have said that the scene the prop was to appear in was never even filmed.
Further, there appears to a a *green crystal* inside the prop, beneath the control box. There are two things wrong with this:
1. The whole notion of lightsabers containing colored crystals surely did not exist in 1982, when this prop would have been built (unless the crystal was added to the prop years--maybe even decades--later).
2. At the time this prop would have been built, everyone thought that Luke's new saber would have a blue blade. Even early trailers for Jedi show the saber with a blue blade. It wasn't changed to green until long after filming was done. So why would this "authentic" prop have a green crystal (or any crystals to begin with)?