S/N is good according to WD site.
My doubt is inspired by this post
http://community.wd.com/t5/Desktop-Mobile-Drives/A-faked-wd2003FYYS/m-p/56320
Relatively many disks (new in package) appeared last time of this model (not another) in small online shops in my city with chipper price then majority of online shops offer. It’s strange.
I have 2 the same disks. I’m going to bye additional 2 disks of the same model. But hasitate. They have the similar behaviour. Above are results of HD Tune of both disks I have.