If i remember correctly , Jim Mattison, who worked in Chevrolet Fleet and Special Order department had some relationship to Berger either family or dated the daughter?
I used to email with him after sending him copies of COPO paperwork that was found with a Yenko Camaro
He said he became friends with Don Yenko and flew on Don's plane with him a few times to go to races. He said Don got him a doctor's note saying he was sick when he wanted to skip work to go to a race
here is an article with info on Jim M
https://www.chevyhardcore.com/featur...tory-approval/
pretty good article but some info is old and not correct