[William]

Many of the magazines that have "Chevy" in the title routinely publish incorrect info. This has been going on so long just about nobody takes them seriously.

In general a COPO can not be identified by VIN or body tag data. Exceptions are ZL1s and Yenko Camaros; all VINs are known for these. (well, PA Yenko Camaros...)

A few guidelines: none are known to have been built in CA ("L" VIN), no L72 cars built prior to 01B. So you can rule out CA built cars and any Norwood car built prior to 01B.

For the rest the only way to be certain is factory paperwork. Being that is way too easy to create a very convincing fake I wouldn't consider a non-Yenko COPO without it.

X11 means it has style trim. X44 means it does not. They are unrelated to what's under the hood.