Continuity mistake: When Dietrich, Gobler, and Belloq arrive next to the destroyed Flying Wing, Gobler is on the left of Dietrich and Belloq on the right. In the next shot, they have switched places. (01:20:58)
Continuity mistake: Belloq, Dietrich, and Gobler arrive next to the destroyed Flying Wing and begin to walk towards the intact wing, while Dietrich says, 'Have it put on the truck.' In the next shot, the Flying Wing and the entrance to the Well of Souls have disappeared from view (instead of the latter, you now see the hut where Pat was). In addition, some barrels suddenly appear between shots, next to which the three antagonists stop. (01:20:59)
Continuity mistake: As the truck pulls up next to the Command Tent, four soldiers lift the Ark's box and a fifth soldier, positioned between the two wooden posts of the Ark's box and to Gobler's right, picks up the sticks that Indy and Sallah had used. In the next shot, that soldier is now to the left of Gobler and the Ark's box. (01:21:40)
Continuity mistake: When the Nazis are loading the Ark in the truck, you can spot Toht next to the left side of the truck, watching the scene. A few seconds later, he walks out of scene, apparently going to the car. However, when Belloq and Dietrich walk to the car and Belloq shouts "Let's go!", Toht has disappeared. (01:21:45)
Visible crew/equipment: As the bad guys are leaving the dig site for Cairo, there is a shot of the black vehicle (lead car) looking right at the driver. On the bottom of the shot is a shadow of film equipment that shouldn't be there. The shot lingers, so the shadow is very visible. (01:22:50)
Visible crew/equipment: When Indiana is chasing the Nazis in the truck, look closely at the convertible, you can see the camera on the windshield. (01:23:25)
Continuity mistake: At the beginning of the Truck Chase, when Billy Horrigan starts shooting at Indy, Reg Harding's right hand goes from grabbing the front passenger seat to grabbing the metal bar of the jeep between shots. (01:23:28)
Continuity mistake: When Indy is chasing after the truck on horseback, he jumps off the horse and onto the truck, as he does this the horse begins to slow down and fall behind, but as Indy throws the German soldier in the passenger seat out of the truck the horse has disappeared, it could not have been hidden from view behind the truck, because the horse's shadow would have been visible. (01:23:30)
Continuity mistake: When Indy is fighting the Nazis on the truck, one Nazi is thrown from the truck and is rolling the opposite direction of the truck. (01:23:30)
Visible crew/equipment: At the beginning of the ark chase sequence, Indy jumps into a truck off a horse and fights the driver. He pushes the driver up against the door. At the bottom of the frame you can see the camera shadow. (01:23:35)
Continuity mistake: Several times during the fight in and around the truck the bars around the top of the cab come off and are miraculously back on again. (01:24:05)
Continuity mistake: When Indy throws Terry Leonard out of the truck, the forest they were driving through disappears. Then Indy closes the truck's door and the forest reappears. (01:24:22)
Continuity mistake: Just as Indy crashes Gobler's jeep for the second time, you can see that beside the desert road is a large forest. However, the jeep falls off a cliff that appears out of nowhere. (01:25:37)
Continuity mistake: When the camera shows the back of the truck, there are two soldiers on each side of the truck, plus the sergeant inside it. As there were seven soldiers and one of them fell off the truck - there's a missing soldier in the scene. (01:25:50)
Continuity mistake: As the Nazis are preparing to leave Tanis, a soldier fires a shot into the air, causing several Arabs to fall to the ground and land in the middle of a circle of soldiers. In the next shot, as Belloq heads for the car, all the downed Arabs, the sergeant and the circle of soldiers have disappeared, with only the soldiers who were loading the Ark onto the truck remaining. (01:26:55)
Continuity mistake: As the sergeant climbs to the truck's roof, Belloq turns his head to watch the scene. In that shot, the staff car is passing next to a group of plants. In the next shot, almost all the plants have disappeared. (01:26:55)
Continuity mistake: While Indy is fighting the German who is driving the truck, you can see that the German has got blood on his left hand, but when he throws Indy through the windscreen his left hand is clean and there is no blood on it. (01:27:10)
Revealing mistake: When Indy goes through the windscreen in the scene where he is fighting the balding blonde German, the stunt double playing the German has a full head of brown hair. (01:27:10)
Continuity mistake: When the sergeant throws Indy out of the truck window, the adventurer grabs the Mercedes logo with his left hand. After two shots, he is to have let go. However, in the next shot, Indy is grabbing it again. (01:27:25)
Revealing mistake: When Indy fights the driver of the Nazi truck, the windshield is smashed when Indy is thrown through it, but there is no wind. Look at the driver's hair, not one stirs from a breeze while driving a fast moving truck with no windshield? (01:27:30)
Answer: The scene you describe was indeed filmed. It was cut out of the US release of the film although I cannot speak for the Australian version. The scene also appears in the Marvel Comics adaptation. http://www.theraider.net/films/raiders/deleted_scenes.php has a list of this and the other deleted scenes.
Phil C.