Heinrich is right, the model looks a lot like a derivation of a Panhard AML hull. It isn't exact, but pretty close. The vehicle circled down in the right corner of the image you posted, though, doesn't look like this to my eye. To me it looks more like a Renault VAB 4x4:
http://home.comcast.net/~storto10/vab1.jpg The aft portion of the vehicle in the movie image seems to be more slab-sided and sloped than the back of the AML. I'm gonna have to go look at that section of the film.
The model looks like it was derived from a toy AML as the details seem a bit coarse and the tires are definitly not as detailed as a proper kit would be. It would also explain the differences between this model and the real thing. Toys can be close. but are seldom exact.
Pretty cool, though.
Paul