Looks nice, but is it really a GS? Not even mentioned in the ad. https://www.hemmings.com/classifieds/dealer/buick/riviera/2200198.html
It's also got Chevy wheels. According to the sales brochure, there was a GS option in 68. It had a chrome aircleaner and was probably offered with the Custom trim. I'm sure one of the Riviera experts will chime in if it's real or not, I frankly don't know on these.
