Just because there's not a sticker, doesn't mean there's not a certain package on the vehicle. I debadged my current tundra, including the SR5 badges and TRD stickers.
Believe the VIN is coded to indicate trim level, including the TRD package. Just google on "Toyota Tundra VIN decode" and you should find one easily enough. Then compare your VIN to that decoder and you'll see how it was configured at the factory.
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