I know it is late, too bad I didn't see it but the back of my double dragon II manual says if the game doesn't have the Winners screen then it is a bootleg
Gamefreak is right, Hammer and Spike which the international names, Billy and Jimmy are the Japanese names that the story line used. The gang in Double Dragon was the Black Warriors.
The Kanji characters in the title screen are (in order): 'Sou' (Twin) 'Setsu' (also pronounced 'Sai') and 'Ryuu' (Dragon). Sou-Ryuu is another title for this game
Most of the character were named after "Enter the Dragon" movie with Bruce Lee.
Yeah, you can read alot of the trivia from klov and the history.dat
I should find a JAMMA cabinet and hookup my ddragon 1 and 2 board to see which versions I have

I probably have the US international versions.