[COPO]

Suggest you start doing some research from the various printed material if you are serious. Since you didn't specify which COPO, I assume you are referring to the most common COPO 9561, ie. a 69 camaro w/iron block 427.

Beyond the obvious engine block numbers here are a few other things to check.

1) Silver grille (common to all non SS cars)
2) Single 3/8" fuel line from gas tank
3) On Norwood built cars X-11 or X-44 on cowl tag. (Having these codes does NOT mean it is a COPO 9561, could be a base car or an SS 350)
4) check for a 4 core radiator (most COPO's had curved neck)
5) Check driver's side outer rear frame rail for welded plate indicating the car came factory equipped w/dual exhaust.
6) most importantly check for "BE" coded rear axle. unique to COPO cars
7) cowl induction hood.
8) power disc brakes.
9) re-read the above post.

That's all that comes to mind. Good Luck!