Need help decoding a 1972 Blazer
 

I have a 72 K/5 Blazer, and was wondering when it was built and how much it originally cost including the price for each option that it had. Somewhere in it's history, someone either changed out the passenger door, or the sticker was removed so that the truck could be painted. I do have the original protect-o-plate. Does anyone know the best place to find this information?