http://www.ebay.com/itm/Super-Mario...185&pid=100033&prg=1011&rk=4&sd=380635597547& To me, this looks like it could be legit. Also, I find it interesting how the pins are soldered together rather than being connected with one of those bridge connectors Nintendo used for the first NES games released.
It's nothing more than a pirate cart. http://www.nintendoage.com/forum/messageview.cfm?catid=35&threadid=97258
There is no such thing as an official Famicom cart version of Super Mario Bros 2. All such carts are bootlegs. Edit: Beaten by Lum.
The only official cart release is for Super NES Super Mario All Stars. Super Famicom has it as well. No legal 8-bit Famicom cart at all.