It depends on how you define complete. This is apparently the final build they made for the N64.
It is nearly complete as in all the content they made up to that point is included in this version. Even the final boss battle appears to be there, in a rough state.
But since this build was never supposed to be playable by the public most of the later content can't be seen without hacking the game. They hadn't tidied up the event progression yet to the point where a normal playthrough would be possible.
The E3 version had a level select menu that allowed you to play specific parts of the story in any order but our build does not have that menu. Fixing the game from beginning to end is going to take a lot of time.