Freezer to Fridge?
Doubtful. Freezers have an evaporator coil that runs under every shelf throughout the freezer space. With that much cooling going on you're still going to freeze things by the nature and design of the system itself.
Also, these older units normally had a thermostat capillary mounted directly to the evaporator. Operation depended upon evaporator temperature, not the temperature inside the box. You'd want to get a thermostat that will work right to avoid swings in temp in between cycles.