I bought it used. Who the hell would sell a fake as used on ebay?
Anyway, the PCB has the nintendo logo in gold lettering on it, I dunno how more official you have to be.
And it works just fine after I put a battery in it. Hell you don't even need a battery for the saves since they'd moved to non-volatile memory by then, it's only for the RTC
besides, I know what a fake ebay entry looks like thank you very much