This is the 1/4 vertical seal for the full size coupe as shown below.

Metro USA.     

This part also fits the following autos:
1967 BUICK ELECTRA
1967 BUICK LESABRE
1967 BUICK WILDCAT
1967 CADILLAC CALAIS
1967 CADILLAC DEVILLE
1967 CHEVROLET CAPRICE
1967 CHEVROLET IMPALA
1967 OLDSMOBILE 98
1967 OLDSMOBILE DELMONT 88
1967 OLDSMOBILE DELTA 88
1967 PONTIAC BONNEVILLE
1967 PONTIAC CATALINA
1967 PONTIAC EXECUTIVE
1967 PONTIAC GRAND PRIX
1968 BUICK ELECTRA
1968 BUICK LESABRE
1968 BUICK WILDCAT
1968 CADILLAC CALAIS
1968 CADILLAC DEVILLE
1968 CHEVROLET CAPRICE