If I bought something from someone and It might have got messed up during installation

, and the person i got it from included everything like the warranty card serial #s everything, and I regerstered for the warranty online would it have warranty under my name? it asks the date it was purchased and how much and where...if i put some good info there like bought it from bestbuy, paid like 700, and date was today, would they actually check that? is there even a way for them to tell when it was or even purchased from?....
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