56 Dodge Sierra wagon D-500

I bought this car on Ebay turned out it was located in my town. I have verified it's authenticity as well as the gentleman I bought it from got it from original owners family. I will be painting the car next week. I located the correct material for the front seat and is being recovered now. All the mechanical's are perfect. drive train original to the car and engine stamped D-500 as well as all the other options they were equipped with, I read these are very rare but cannot find info on the real numbers that were produced. The numbers I hear are 10 to 13. I am trying to value the car for insurance purpose, it will be considered average condition. Also anyone with info would be much appreciated.
Author: 34bud