1950 Buick Special
It would be a Super or Century if it had four portholes. Though I still think that b-pillar looks much too large to be a Riviera model.
1964 Buick Riviera 425 Nailhead V8 - Low Mileage Original
1965 Buick Riviera 1024 x 770
1965 Buick Skylark Gran Sport hardtop coupe, part of the 1965-1967 Buick Skylark
... 1967 Buick Riviera - GRESHAM 97080 - 5
1969 Buick Riviera
Ccrp 0908 05 Z+1969 Buick Skylark+rear View