Registering a warranty on 2nd hand bike

[avfc_66]

Hi all,

I have been offered a Rail in my size with about 40miles done and the warranty not yet registered by the original purchaser.

My question is how can I be sure it hasn't been registered? I know that Trek offer a 3 year warranty (in place of the lifetime warranty) on the frame for a second owner but I'd like to make sure that I have the original owner warranty, seeing as that is what's offered!

Thanks all