This may be common knowledge and if it is I apologize. As I was watching ANH DVD last night I started watching the attack scenes frame by frame. As I did I discovered what I think happened with the AMT kit and why it has that funny kink in the bottom of the fuselage. As the X-wings fly down the trench and viewed from the side, the way they are lit and the shadows formed on the x-wing make it look at times as if the fuselage flattens out just under the cockpit. It appears as if the light is coming from the opposite side and also lights up the bottom of the craft. If these scenes are what they used then I can see where they goofed.
On another note, it has been a while since I've watched the movie and I have forgotten how much fun it is. Makes me feel as if I was 11 all over again and have just seen the coolest thing ever.