Advice on hub oil port

[DelombardR]

I am cleaning up a Lenox bicycle (ca 1895) and need some advice on what I assume is a port for oiling the hub bearings. As you can see in the photos, there is a nut centered on the hub. I have no experience with these, so do not know how to proceed. Does the nut come all the way off to add oil or just loosen it up?

Any tips or suggestions?

I'm going to try and keep the bicycle as original as possible, but to ride it will probably use 'cheater wheels'. These spokes are real weak.

[58inchwheel]

It is most likely a one piece item that just screws (actually like a small bolt) on or off the hub. I have had some that screwed or bolted onto a guide on the inside to flow the oil to the bearings.  To add oil just push in on the center part. It’s a spring loaded ball. Hope that helps