That is a tough one.
I was in a similar situation back in 2002. I had a new 2001 Silverado Z71 and was rear ended at a stop light (by a guy going 35mph reading a map). It had 15k miles on the clock and the Ford Aspire that hit me did ~$6,000 damage to my truck. After I had it fixed by the best place in the area, it was still never the same. I had problems after problems with it and eventually traded it in.

My friend was the sales manager there and he said it would be worth less than one not wrecked, but they were not allowed to go on record saying that. Luckily I got a good deal on the trade since I knew him. There is a pretty famous court case regarding diminished value, but I can't recall the name.

I'd do a bit of research and maybe consult with an attorney.