Continuity mistake: When we first meet Francisco Scaramanga we see that he has a third nipple which is just above his left. The next time we see him he is lying on a beach chair showing the left of him. If you look carefully you will notice that there is no third nipple. (00:06:33)
Continuity mistake: Bond tells the kid he'll pay him 20,000 bahts if he manages to start the engine, which he does. Shot changes and the kid spreads his arms wide and smiles with joy. Back to the wide shot and his arms are closer together, and he has a worried look. (01:00:30)
Continuity mistake: When Nick-nack realizes that he and Scaramanga are being followed, there is no round, white decal at the lower corner of the windshield of their AMC Matador, yet in all other shots, the decal is there. (01:22:20)
Continuity mistake: The AMC Matador stops as the AMC Hornet X races by on the cross-street. As the Matador halts, we see it has a proper door mirror. In a close-up of Scaramanga driving, we can just see the hole in the door where the now-missing mirror was mounted (on the VHS full-frame, we can see the remote cable hanging from the hole and the base of the mirror swinging as the mirror hangs out of view). (01:24:20)
Continuity mistake: A significantly modified '74 AMC Hornet was used for the famous cork-screw jump sequence, taking the place of the relatively stock Hornet X used in all other shots. It is best viewed just after the jump as the car slows to turn left - the car has a much lower stance and the wheel wells are far larger. (01:26:50)
Continuity mistake: When the AMC Matador arrives in the hangar and begins attaching the jet plane equipment, we see a bracket welded to the lower rear quarter panel, just behind the door. The wing supports swing down to attach at this point on both sides of the car, yet these brackets were not on the car in any prior shot. (01:27:35)
Continuity mistake: When Bond is flying over China and landing on the sea by Scaramanga's island, you can see that his plane has two floats - one on either wing. But in the shot where he is heading for the beach, it is clearly seen that the left float has gone! (01:28:40 - 01:30:55)
Continuity mistake: When Scaramanga is talking about the laser gun to Bond, the water is next to his airplane but when he shoots on it, the level is lower. There's only little waves so it's impossible to change that fast. (01:36:55)
Continuity mistake: During the chase scene with the police, Bond swerves past a driver in a dark green 1956 Plymouth Savoy. As the police cars pass the Plymouth, the scene cuts to an inside shot of the car with the driver yelling. Then, the driver loses control of the car and rolls it over. The car that crashes is a green 1955 Chevrolet 210 series, not the 1956 Plymouth.
Continuity mistake: The red AMC Hornet X that Bond steals from the car dealership alternately does, and does not, have an interior rear-view mirror mounted on the windshield.
Continuity mistake: At the start, when the gangster is preparing for the showdown with Scaramanga, there is a rope hanging with a knot in it, however, when Scaramanga comes in the knot in the rope has been tied.
Continuity mistake: When Bond is picked up by the Sumo wrestler in the garden Bond is upright hitting the wrestler. When they cut to the wrestler front (Bonds backside) Bond is already down over the wrestler's shoulder doing something to the wrestlers backside. They cut back to Bond front side and he is still up and reacting in pain and then bends over the wrestler's shoulder.
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.
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.
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]