Luke, are you parting out "my" truck? LOL!
Angi, the oil pressure and water temp gauges are mechanical; the oil line connects to a fitting on the driver's side of the crankcase and the water temp line is a closed capillary tube that screws into the cylinder head. Be careful with the capillary tube to the temp gauge, I got a kink in mine and the genie inside got away. Now the gauge doesn't work at all.
Ammeter and fuel are the only gauges that need electricity, so check under the dash to see if there are leads for them. If the wires have been cut, I think you'll be better off getting a new wiring harness from one of the vendors rather than patching a bunch of old bits together (definately get a new harness if the insulation is rotten).
