Does anyone know where to find the paint code or number for a 1997 Lumina? Is it on the door or the trunk? There is a number that starts with a "P", would that be the right number?

In the trunk, usually on the spare tire cover.
There is a label with numerous alpha-numeric codes printed on it.
The paint code is usually two numbers and the letter "U" like 92U or 45U, or something like that.
I hope this helps.