Yes, if she had driven down the embankment, the front plastic cowling of her car would have suffered a ton of damage. As you can see in the video I posted earlier of the car being towed, the front end of her car has virtually no damage what-so-ever. That entire front end is plastic. The windshield and the top of the car seem to have taken the brunt of the damage, which pretty much means the car would have needed to be upside down when it hit both the water and then after settling on the bottom of the river.
Personally, if that car had just been pushed over the upper edge of the embankment and allowed to roll downhill, I have serious doubts that it would have ever made it into the water. There's too many rocks, ruts, and obstructions on the way down to the edge. I think the car would've definitely snagged on something as it rolled downhill. On the other hand, if the car was moving at 50-60 miles an hour, it could have easily gone airborne over the steepest part of the embankment, the front of the car beginning to nose dive due to the engine weight, and did a slow motion somersault until it landed windshield first into the water. That's really the only way I can envision this happening with a complete absence of damage to the front end, and very little damage to the sides of the car.
Whether this was a deliberate act or an accidental act is still left to be determined. I don't know that they will ever really know for sure unless they find a suicide note or something. It could also have been a criminal act, with the gas pedal being depressed and held in place with some kind of an object. That in itself would be very risky though, simply going by the terrain. There are many other smoother places you could find to cause a car to go running into a river than the place her car was found. The chances of it actually snagging up on something and only ending up partially submerged are pretty high.