* A specific internal code: This is the most probable explanation. P-codes are often used internally by manufacturers to track builds, options, or even problems during assembly. Without more context (like a build sheet or service record), it's impossible to say what P10 signifies.
* A misinterpretation: The information source might be mistaken or the code was partially obscured or incorrectly transcribed.
* A dealer-specific code: Some dealerships use their own internal codes.
To understand what "P10" means in relation to a specific Chevy truck, you'd need to provide more information about where you saw this designation (e.g., a sticker, a document, a website) and the specific year and model of the truck.