Sorry, but that is not only dishonest, it is called Insurance Fraud. People have gone to prison for that. Although, as RRR stated, it may be the only way you will get money, it is still dishonest and illegal.
I had a dealing with a company exactly like that when that daughter of the elderly lady across the street backed into my 98 Dakota about 7 years ago. I had just finished putting a beautiful, flawless black paint job on it, powder coated the wheels and fixed up the interior. The KBB value was $4500 at the time. They offered me $2700 and they kept the truck. I asked where the HELL they got that value. Turns out they have their own secret book that contains values based on THEIR research of sales of LIKE vehicles in my area. I asked if I could see it, and they said no. I contacted the Kansas Insurance Commissioner, and, strangely, that is legal. I fought with the insurance company for several months to get $3200 and I kept the truck. When the insurance company is one you have never heard of, get ready to get SCREWED!