Dude, if you're gonna change the wheels, change the wheels. I don't think it's going to be a huge perfomance mod or shave a full second off your 1/4 mile time or make the truck fly. Hold a magnet to it to see if it's aluminum. Pretty easy test.

If you're trying to save weight on a 2+ ton truck, talk to IndyRamMan. His truck is stripped to the bone with no tail gate or bumper or spare, etc. I think he has two five-gallon pails in his cab for "bucket seats"...