Is this a COPO?

[Bakes1111]

I have a '68 Camaro SS big block 4-spd with a VIN that shows it was built on the production line right next to one of the Yenko COPOs listed in the 1968 Camaro COPO VIN list. Mine is 8NXXXXX1 and the one on the list is 8NXXXXX2. The block looks like it was replaced with a '69 396 block but all other parts on the engine tie out to proper date coded 68 396/375HP parts including heads/intake. Wondering if block was swapped out at some point.

Can you tell me what I should look for on the car to see if it is a COPO or not? No paperwork available.

It does have 4:10 posi rear and M22 matching #'s.

I know it might be a long shot but you never know. Thanks for your help.