Oil Galley Plug in 360

That's what I was thinking, the oil pump and pan aren't installed yet but its easier to do that than take everything completely apart again. If I have good oil pressure its probable safe to say its there. That's what I would think.

But isn't that plug so the oil filter gets oil? So if I primed the engine and if oil comes out of the oil filter adapter its there? and if not I guess I have to disassemble everything and install it.
I think I would put the filter and a guage on it and then hand or drill prime it and see what kind of pressure it makes.

I guess while I'm thinking about this are there any other plugs that I may have missed? All external ones are accounted for, and the plug that you can see by looking through the distributor hole is there as well.
This one I don't know for sure, but I'd bet it could be looked up.