Serial number on the cover different with the info inside

My uncle just gave me an Ipad air, he said it new. I checked the S/N (DM*******K14) on the cover via Apple website and it says the Ipad still be covered for hardware repair & service up to 3 Jan 2017

But the s/n in General > About is different DM*******K14

Is this normal ? Is it refurbished or replacement Ipad ? Or scam ?

Its model ends with LL/A so may the difference of s/n affect the warranty service?

Please explain, thank you.

<Personal Information Edited by Host>