If you mean the hole where the gauge is hooked up, yes you should be getting oil out of it as that would be the supply line for the canister filter as well as where the gauge hooks up to.
Try rotating the crank about 90 degrees and prime it again.
The "O" means you have one of those drilled head bolts and it needs to be in the center-right hole, assuming they plugged the original oil passage at the top of the block deck. Sounds like it's in the right spot.
The fitting on the passenger side of the head won't give you any oil IF the plugs under the sidecover are missing...
The oil goes from the pump, through a metal line and into a galley in the block which feeds the bearings and the oil filter. If you can't get any oil out of the filter hole, then perhaps you need to drop the pan...
