Is a GMC truck just a dressed up Chevy truck?

The GMC lineup is GM's luxury truck division, that's why you see all the neat things on the GMC truck's. I talked to a good friend of mine who works at the Chevy dealership in town. If you notice, the GMC truck's got the 5 way tailgate and all wheel steering, and the step bumpers before the Chevy truck's did and yes they are more expensive