What is a window sticker?

A window sticker — officially the "Monroney label" — is the printed sheet the factory attaches to the window of every new vehicle. It has been federally required on new cars in the United States since the Monroney Act of 1958, and decades later it remains the single most authoritative summary of how a particular vehicle left the assembly line.

It lays out the standard equipment, the optional equipment and packages the original buyer selected, the EPA fuel-economy ratings, the warranty terms, the percentage of U.S./Canadian parts content, and the full price breakdown — base MSRP, each individual option, the destination charge, and the grand total. That original data is exactly what lets you confirm, years later, how a used vehicle was really configured.

Window sticker vs. build sheet

The two documents describe the same factory configuration in different ways. A window sticker is written for the buyer: plain equipment descriptions, fuel-economy ratings, warranty details, and a price breakdown right down to the destination charge.

A build sheet is the factory's own assembly record — the complete list of option codes a vehicle was built with, without pricing. WindowStickerVin.com returns the window sticker whenever one is on file, and automatically falls back to the build sheet when it isn't, so you always come away with the underlying factory data either way. For a deeper comparison, see our guide on window sticker vs. build sheet.

Why check your window sticker or build sheet?

Whether you're buying a used car, selling one, arranging insurance, or just settling a curiosity, the factory record is the most reliable way to confirm exactly how a vehicle was equipped the day it was built — far more dependable than a listing description or a faded memory.

It lets you verify the trim level, the engine and drivetrain, the option packages, and individual features, and it makes it easy to tell factory-installed equipment apart from anything a dealer or previous owner added afterward. For buyers especially, it's a quick way to make sure a seller's claims actually match how the vehicle left the line.

What does 39U mean on my 2017 GMC Sierra 1500 build sheet?

Exterior & Appearance · 2017 GMC Sierra 1500 · 424 views · 4 replies

39U — Primary exterior color: Aqua Blue Metallic. This code identifies the vehicle's factory-applied main exterior paint color. Browse RPO codes →

Jessica A. Apr 27, 2026 · Texas

I found code 39U while decoding the build information for my 2017 GMC Sierra 1500. The description I have is “Primary exterior color: Aqua Blue Metallic. This code identifies the vehicle's factory-applied main exterior paint color” Has anyone verified what this includes on this model and year? I am mainly trying to understand whether it identifies one component or a complete option package.

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4 replies

Aaron M. Apr 29, 2026

Check the production month as well as the model year. Mid-year changes are one reason two vehicles with the same badge can have different hardware or descriptions.

2 likes

Nick S. May 4, 2026

This sounds more like a documentation mismatch than a decoder error. Different databases often shorten the same factory description in different ways.

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Grace A. May 6, 2026

A clear photo of the build label, VIN report, and the relevant component would help. Do not post the full VIN publicly; the last eight characters are normally enough for a parts-counter discussion.

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Ben Y. May 10, 2026

Check the production month as well as the model year. Mid-year changes are one reason two vehicles with the same badge can have different hardware or descriptions.

3 likes

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