He's right.
It's available with ZY5, which is the two tone paint scheme, or with some other special packages (Sport Truck, Diesel, for example).
https://www.gmheritagecenter.com/doc...olet-Truck.pdf
I don't have any detail on your truck, so I can't say for sure what might have driven a hood ornament. Could have been a mis-build and they decided to give the hood ornament away. Or the hood could have been swapped at some point in the last 40 years.
Thank you for the kind words -
K