Help - Stock Oil Pressure Gauge Fitting

[tdangle]

I finally am getting my truck back on the road. When I removed the gauge cluster I disconnected the oil pressure line at the engine block and put a plug in the hole, so I could run the engine and be able to move the truck. Now I want to hook it back up and don't remember removing a fitting from the line to the block. Is there one that I lost? all I have at the engine side is a nut on the metal line. anyone have a picture?

Thanks