I'm with the guys on the RPF. Everytime some item from Gary Kurtz's collection shows up on for auction it has T-tracks on it that don't match what we know from the OT. I have no doubt that that graflex was actually used in the films but I agree with some of the RPF speculation that it was probably a torn down prop that was rebuilt from parts, perhaps at Elstree. Regardless, 200K is a lot. As for donating props like that...no fear as Lucas has most of the best prop sabers are in the archives.
Well...other than the Vader ESB/ROTJ hero saber which appears to be in Pennsylvania and the Obi-Wan ANH hero which is lost to time and the Luke V2.