Oil Pressure Sender...?

[mrlobster]

I just noticed today that the oil pressure port on the back of my 350 by the distributer has a sender with a wire, as opposed to a fitting with an oil pressure line. The truck (72 GMC)originally came with idiot lights, but the previous owner swapped them out for temp/amm/oil gauge package. Can the oil pressure for a mechanical gauge come from somewhere else on the sbc? Also, can I simply now run that wire to an electrical gauge?
I had to park the truck right after I bought it, and the cab is under a foot of snow so I can't just pop the gauges out and look what's going on back there.
Thanks!