I understand from talking to the current owner's son that Walters Chevrolet (now Bowman) in Hebron sold one COPO Camaro, one COPO Chevelle and one Yenko Camaro. I've been able to confirm the Camaro and was also recently able to confirm that they had a Yenko on their lot. The below image is an edit of a full page classified ad from late August 1970:
Seems like $200 wasn't much of an ask to go from an SS350 to a sYc... Wonder if it was Rally or Fathom Green?