oil pressure sender - is this it??

[centuryhouse]

I have a 72 GMC but have been told by two forum members that my engine looks like a crate engine replacement. The seller of the truck told me numerous wrong things, but did say the engine had been rebuilt or replaced in the 80s.

At any rate, the oil pressure gauge doesn't work. I am trying to find the sending unit.

I see a tiny brass (?) tube leading into the firewall near the instrument panel, with a screw in fitting on the end, but it leads nowhere and I don't see anything it might plug in to.

Also, I see a small unit right next to the oil filter, which a wire should clip on to.

Can anyone tell me if it could be that my dash uses a wire connecting instead of tube connection? Or what might need to be done with these two tings (the tube and the wire connection)?

72 GMC 350, automatic, 2wd.