Even if the officer does read it, he's not obliged to believe that the document handed to him by the driver is what the driver claims it to be, or that it means that the driver claims it means.
In several states, carry permits are a form of affirmative defense. That is, you're assumed to be engaged in unlawful activity until you
can prove otherwise, usually by producing documentation. However, law enforcement isn't bound in such cases to accept the documentation. Affirmative defense is generally applied at the trial level, not the arrest level.