Are you sure it was Unrealed 1? I mean that's the visual basic one, even the last patches of UT got rid of it and replaced it with UnrealED2. The version of UnrealED hardly says anything about the engine though, but UnrealED 3 is what unreal engine 2 games use.
Though there are in between games which use UnrealED 2.5 and similar, but those are usually running on the "warfare" engine already, which to some people is still mostly the original engine but with upgrades. Many people disagree where exactly the split is between UE1 and UE2. It wasn't even called that way originally and only retroactively, which makes it worse. Some people say its the render.dll that actually is the clear split but there are corner cases always.
I'm also thinking that this game could be a good base to port Circle content to, as opposed to regular Unreal because it has the basics already working for that type of game. Well except that I don't have the game and that I will be confused by all the chinese symbols I guess.