Apple adaptor real or copy ?

Hi Dimers,

I recently bought an apple adapter 20w from tata cliq app and seller is 'Anik'

I want to know how to check for authenticity to make sure it's original and not copy.

Checked in bis care showing as " Salcomp Technologies" as  manufacturer and some how serial number check against coverage in apple site showed invalid.

Please provide your suggestions if anyone bought from the same seller and long term usage experience