Fuel System Question

[1972BlueC20]

I have a 1972 3/4 ton C20. There is no charcoal canister. The gas tank has only 1 main solid filler neck. The sending unit has one large hose and one smaller hose both running to the fuel pump and each hose goes into the pump at their own seperate inlets.

I recently replaced my fuel cap with the one the stant website called for #10623. It was identical to the one that was already on the truck when I bought it.

My question is, did my truck come from the factory with a charcoal cannister? Should I have a vented cap or not? Searching posts on this forum, has people saying mostly that a vented cap is needed. But there are a handful of people saying I should use a non vented. I went with the majority and what stant said on their site and got the 10623 vented cap. Is this correct or not???