The Salon was aimed at the sportier crowd--usually a console, buckets, rims, amber parking lenses, less trim.
The Brougham was for luxury--plush seats, lots of trim pieces, creature comforts, etc.
Neither was considered to be higher than the other--these two offerings were just Oldsmobile's way of hitting two types of buyers with one car. The RWD Cutlass was well thought-out and because of that became the bestseller.