Looks to be an original rust free western Canadian car and Price is right. https://www.kijiji.ca/v-classic-cars/calgary/1968-buick-riviera/1570935228
Not bad, rear bumper looks a little ganked....maybe bolts are just loose, hopefully not bent. Has the ultra-rare 4-piston Bendix front disc brakes, too....hope he has some spare rotors for it, because nobody sources them.
Different rear side markers, passenger side (Tri-Shield) is the right type for 1968. No power windows, no DeLuxe interior and no A/C, but it came with the cornering lights option.
I posted this car before in this section of the board, May 28 2021. Asking price was a little higher in May: CAD 8,800 (now it's CAD 6,500)