Well bitrot is possible. I don't know if anyone will bother trying to figure out if it occurred or not. If it was originally like this and was supposed to run with this revision of the other roms then I guess it's got to be a proto in which case I don't know why it ever left the bootlegger's hands... Luckily for playing in mame, attract mode isn't necessary. So it's cool that we got it even if a rom is slightly bad.