Good Morning 'A-Body'
Yes, those Headers found in the trunk of the 'Optional DZ' Z-28 Camaro's
were fabricated by 'OK Kustom Headers', and with a GM {Part #}.
If you ever find a set of them, wrap your arms around them, and run home and hide them in a 'safe place'.
They are worth a 'Boat Load of Cash'......... $$$$$