The cabs are interchangeable. The gas tank may have been mounted under the frame on a 1.5ton. But you could use it under the seat. I think the radiator support frame is the same but a larger capacity radiator. The engines and transmissions would be the same if the 1/2 ton was optioned with a 4spd(except the 1/2 has an enclosed drivetrain). Otherwise the brakes, frame, and drivetrain are different from 1/2ton. You could use the rearend from the 1-ton, it should be the same. More of the parts from the 1 ton are interchangeable with the 1.5ton.
