How hard would be for Chinamen to buy one original unit and then copied the number couple of times. Just example that checking serial number doesn't mean you safe to buy.
I bought my second hand 5k from an Asian guy in Melbourne, unopened and never registered nearly 3 years old. Everything looked genuine, phone checked the serial number(which didn't helped much, as never registered) even in Miners Den Melbourne told me it's genuine.Everything looked so suspicious.New, unopend, never used for 3 years and the guy was selling it for his brother who lives in Adelaide and apparently couldn't sell it over there. I can tell you I was in doubt until I started finding gold.