I find it hard to belief that insurance companies would insure for significantly more than the current value. At best they might use a year or two out of date values. Paying a claim for more than the value is betterment and is very undesirable.
Look at it from the insurance cost point of view. If AC insures a plane at twice its value, it has to pay twice the premiums (for hull insurance rather than liability). AC isn't going to want that any more than the insurance company.
Gambling on loss rates is exactly the opposite of the point of insurance.