Is a GMC truck just a dressed up Chevy truck?

The whole Dodge/Plymouth "luxury" thing is kinda blurry.

C body VIP vs Monaco?

B body Satellite/GTX in 66 and 67 has WAY more extra cost "trinkets" than Coronet 500 and R\T.
(but they do have a squeaky/bendy plastic mount for the headlight switch vs the Dodge metal dash area)