what proof do we have that 1969 383s came with chrome Valve covers?

I sent that to a friend of mine . His family owned the Buick dealership in Pocitello and he remembers that dealership.
He told me about taking a Buick GSX fresh off the transport to the drag strip with a mechanic and sneaking it back on the lot before his dad found out !
They also owned the Toyota franchise so they got tons of musclecars in trade starting 72-73...