It works right? So get off the guys back. You bought something used off of eBay perhaps stolen but I doubt it. Not too many thieves go after and sell a lilliput. They arent common enough to be notable. They rip it out get confused and trash it probably because what they thought was a radio, turned out to be some screen.
If it works, shut yer yap. And it is used anyways, so more than 1 owner meaning any warranty the thing would have had, is null and void too. Many many things come with serials number intentionally scratched off or written over. Example, I bought a refurb netgear 802.11g usb dongle from woot.com during a wootoff. When I got it the serials were all written over with big black permanent marker. Because some times when you register a product with your info, the website uses that serial to log you in not a username/password so you can get the previous owners name/address. In my case the thing is crap anyways and barely gets a signal but for $5 with $5 shipping, it was worth a try!