[enine]

Soldering is not difficult, any time you buy parts like that any seller will disclaimer because they don't want people trying to return items after melting them with their 120W gun or having somehting not work and try to pass the blame. If you can solder rc stuff then it won't be a problem.
I would start the truck and let it warm up for say 15 minutes so the temp and oil gauges are near center then take a picture with a digicam and print that out. then disassemble the dash, do the work and put the cluster back in with the glass off and start the truck and do the warm up for the same amount of time so the gauges are in the same place then put the needles back on in refernece to the picture.