Well, since it is only 1gb the chances of it being real memory are pretty good. Most scammers these days advertise 4gb or 8gb ones. Plus, it has expandable memory so you can add a mini SD card to it. That always helps. To check the actual memory size and prevent format errors, follow the instructions here: http://www.mympxplayer.org/how-to-removing-memory-hack-vt2400.html
I would say that it is a clone of the Onda, not the actual one. Your link to the player says it plays AMV video files. A converter should come with the software, but if not, check out the downloads sections. The newest converters can be found there.
As far as upgrading firmware, I wouldn't do it. There are so many types and versions of firmware out there you might get one that is incompatible and you will brick your player.
Hope this helps.