Well this is your half and half cousin part slick and part fridge checking in. According to the 61 service manual and you can take it for what its worth. The heater hose that connects to the flow valve goes to the water manifold connection the other goes to the pump. Thats on a 61 so not sure if your fridge truck would be the same. Yup sounds like your bed was farmerized. Sorry to all the farmers reading this nothing against doing what they did. Please make the welds straight if your gonna make them.