Just a few more thoughts on this, found it when researching something else...
From an insurance pov, a code 3 vehicle poses problems. As there is no retail value or market value for these vehicles, most insurers will struggle equitably indemnifying the policyholder.
Many motor dealers don't want to take the vehicles in trade-ins or sell them on, as their reputation is at stake. Consider the consequences if the dealer sells a vehicle which has a chassis with questionable integrity. One more collision may not protect the occupants of the vehicles, as it would if it weren't previously damaged.
So many insurance companies will prefer not to insure these vehicles. But if they do, depending on how the insured value of the vehicle was determined, you could see a deduction of 25% - 40% depending on the merits of the specific claim.
With no market value for the vehicle, it becomes a logistical nightmare to ensure that an equitable value is agreed. This is also referred to as "agreed value" and it usually comes with certain conditions such as how agreed value has been agreed, determination of value through renewal cycles, basis of settlement and agreement of loss, etc.