1972, 1976, and 1980 Steering Column Ignition Key and Door Lock Key Blank Square Head Reproduction includes the key knockout. These are the primary keys that would be used for the dash ignition switch and the door lock button lock.
These reproduction primary keys are the "finishing touch" for any 1972, 1976, and 1980 Corvette restoration. Raised letters - GM Mark of Excellence - is on both sides of the keys.
When your Corvette left the factory, it was equipped with two of each primary and secondary keys.