Continuity mistake: When the Hong Kong police are chasing Bond, they use three black and white AMC Matador sedans. When they arrive at Scaramanga's hanger, we find that two of the three Matador police cars have been resprayed in red.
Other mistake: Ms. Goodnight was surprised to learn that the car had become flying. There is no way she wouldn't have heard the jet engines and felt the take-off. Also the noise in car's boot must have been loud, but she talked into the walkie-talkie and it came out fine.
Continuity mistake: During the car chase scene Bond overtakes a blue car partially off-road. We see Bond's car almost getting side-by-side by the blue car before we're getting an in-car shot of Bond's car being just behind the blue one.
Continuity mistake: When Bond goes into the belly dancer's dressing room, at first she does not have the golden bullet in her belly button, then she does.
Continuity mistake: During the belly dancer fight, Bond is pushed against a corner and the painting next to him remains unharmed. A shot later, from a different angle, it's skewed.
Continuity mistake: When Scaramanga blows the Bond dummy's fingers, the first shot blows the middle and ring fingers, and the second shot the pinky. When the angle changes, the index finger has also disappeared.
Continuity mistake: After Scaramanga kills Hai Fat, James meets Goodnight in a bar. As they drink the Phuyuck 74, Goodnight's fingers change position on her glass depending on it being a front or rear shot.
Factual error: J.W. Pepper refers to himself as "Sheriff J.W. Pepper, Louisiana State Police." Sheriff is a local office while the state police are a state agency. A person can't be both.
Deliberate mistake: In the scene inside the belly dancer's dressing room, during the brawl Bond has with the KGB agents, he shoves the bald headed guy into the mirror along the bottom 1/3rd of the glass, yet the middle along the left hand side of the mirror makes it look as if that was the initial point of impact before it shatters.
Character mistake: In the scene where Scaramanga invites Bond for lunch, at the dinner table Scaramanga tells Bond he would like to with duel with him, Bond asks Scaramanga "My six shots to your one?" referring to his own Walther PPK and Scaramanga's Golden Gun. The Walther PPK can hold 7 rounds per magazine, plus one in the breech, and he has not used any rounds before that shot in the same scene, so he has 8 shots available, not 6.
Answer: I haven't been able to find any information on its whereabouts so my guess would be that ended up like most movie props do. Either as a souvenir for one of the people attached to the movie, (actor, director, etc.) in storage (in case it could be recycled as a prop in another movie) or simply discarded when it wasn't needed anymore.
Andreas[DK]