If it is legal tinting, there should be a decal, usually on the driver's window, about where the doorlock is located. The decal should have the tinting company's name and % of tint. At least that is how they verify it in my state.
2007 LT 2.2
GMPP Air Intake * GMPP Extrude Honed Manifold * GMPP Cat-Back Performance Exhaust * Vibrant D/P * Jet Stage 2 Module
MOBIL 1 Synthetic Oil * DC Sport Strut Tower Brace * Color Matched Mirror Covers * EuroAntenna * 30-15 3M FX Tinting
Bridgestone Potenza Pole Position RE960AS on Premium Wheels
2.4 Intake Manifold Conversion * 2.4 TB * TUNE