gc valve wiring

got a question on wiring up my gc valves. There are 3 prongs like this | _ | I searched to find out how to wire them and I keep seeing everyone saying to run a hot wire and a ground to the vertical posts. However I found my gc paperwork and the diagram on there shows a vertical post for hot and the horizontal one as a ground. Will it work either way? Im just trying to save a headache down the road after the tank and valves are installed in my truck.

I am pretty sure that post is a ground as well but you don't have to use it. Just run a power and ground to the posts opposite each other.

you use the 2 vertical ones, the horizontal one is optional