What is the difference between a 1972 Buick Riviera and a 1972 Buick Riviera GS?

[Neptune_Rising]

My friend is looking to buy one and I want to understand the difference between the regular one and the GS. Thanks.

 

[LARRY70GS]

My friend is looking to buy one and I want to understand the difference between the regular one and the GS. Thanks.

Besides the emblems, the car would have come with a posi rear, it also had a more powerful 455. At least some of the Rivieras in 71-72 had the Stage1 heads which had bigger valves 2.125"/1.75" vs. 2.000"/1.58". There may also be cosmetic interior differences.