I don't know. For most of us a serious short burns a fusible link open. Someone states that your model doesn't have a fusible link. Again I don't know.
If everything inside the car is dead, there is a failure wherever the weakest link is. That should be the fusible link but... Maybe in your case the amp gauge shunt is the weakest link. I would imagine terminals in bulkhead connector would be weaker but again... I don't know. Good luck with it.