Thanks for the build sheet pic bbdon. On the lower part of that sheet is where I would expect to see a COPO number or special instructions. I'm only guessing on this but that is where some of the COPO Camaro and Chevelle sheets had COPO numbers.
Kevin, I hope I don't sound too critical of your Yenko Nova because I would not want to discourage you (or anyone) from coming on this web site. I wish more SuperCar owners would come on here and discuss their cars. (and submit cool pics) My main curiosity is how Gibson arrived at the conclusion that the car is a COPO non SS Nova. I have not seen the car or the documents so I can only ask questions. There is a good Nova site by Scott Windle where he has a Gallery of Nova pics and a History page. If you scroll through the 1969 Nova pics the difference between an SS grill and the std. grill stands out. The SS grill is blacked out and has two silver horizontal bars where the std grill has a silver grid appearance. It appears that your Nova has the SS grill (without the SS emblem) in both the restored pics and the original pic. (Don C. may know more about this). The "mailbox" on the hood of the original pic prevents viewing of SS grill holes (if there were any) and the back of the car is not shown so we can't see the panel between the tail lights (if it had it). It doesn't have the "396" sidemarker but Yenko would remove that to add his 427 emblem. In the pics of the restored car back view it looks like Gibson used holes from where an SS emblem would be to mount the Yenko and 427 emblems. In the rear view pic the emblems look staggered like on the Yenko Camaros. This was done because they used the staggered holes of the original Camaro bowtie emblem and drilled two more outside holes. If the car was a non SS it would have no holes and I would guess that Yenko would mount the emblems straight like on Yenko Chevelles but this is just my opinion.
Here is the link to the Windle Nova site which also has copies of Chevy letters about the 1968 COPO Nova (submitted by Ray M.) and also interesting story on the 1963 Nova fastback (3 made)
http://www.novaresource.com/