All the models ARE there. Just click on the body and right click and choose "hide selection". Then right click and choose "unhide by name" and pick your model. Then If you don't see that car in the Material Editor, just use the "eye dropper" and click on the body of the car.
Truckseries is absolutely right. Try to "Ungroup" the car and choose to hide the engine or the "Under-hood" which might be displayed as "Hood_U" or something like that.
No, what I mean by the others aren't there is I went ahead and deleted them so that they wouldnt be a factor at all. I have merged your scene into a new one, even imported just the hood from an entirely new scene (the BR15 original) and still had the same issue.
The next thing I did was create an entirely new scene from a freshly opened 3ds max, imported another model car (the Dodge) and had the same issue, again in all of the 3ds Max version.
I have ungrouped, remapped UV wrapped, UV Un wrapped, applied different textures (I.e a brick texture) with no luck at all. My next option was to just remodel the entire hood.
When I get home, I am going to try what home, I am going to try what TruckSeries said and see how that works out for me.