yes, but NCsoft still controlled the distribution and usage. You'll find that many companies can - and will - object to people passing on further things they themselves are giving out for free. It's a question of control.
This is true but just because a company deems something illegal, it doesn't automatically make it so. Have in mind that it is a well known and widely abused scare tactic to send letters filled with threatening legal lingo to people to whip them into submission even though the basis for the claims is questionable or has never been proven in court.
Back to the original question: the answer is somewhat complicated and relies on many factors. First it depends where the server hosting the files is located as it usually the law of the country it is physically placed that regulates such things. What would be illegal in US, could be legal in EU and vice versa.
Second, well, for years the game was distributed for free and was widely available from NCsoft servers as well as many unauthorized mirrors. In case NCsoft would be interested in pursuing a person who is distributing the game client now that the game servers are closed, they would need to prove that the act of closing the servers somehow changed things and that the court should ban something that they previously deemed perfectly okay for 8 consecutive years. I think they would be at a disadvantage here.
Third, what is the worst thing that could happen to you if you were to host, got dragged you to court and lost? The most likely outcome would be that the court would tell you to stop redistributing the file and that's it. There are no damages to speak of, since the client never generated money for the company and I am assuming you weren't taking money for it either.
In truth, I doubt that NCsoft would take any real legal action, though. Most likely they would send you a few angry letters if they knew who you are in the first place and if that didn't work, tried to argue with the hosting company that the file should be taken down. If that failed as well, they'd probably give up.
So to sum it up - you probably won't get a merit badge for it, but illegality of you redistributing the game client is doubtful and it would be up to NCsoft to prove it.
edit: whoops, Peregrine Falcon beat me to it.