Yeah. The stars were just made up.
Tyson brought it up after hearing Cameron go on about the attention to detail that went into the movie... which was true in terms of the sets, props, costumes, etc., but apparentky not the stars, despite the fact that they could have easily punched the date, time, latitude & longitude into a number of astronomical tools to get the exact sky over the North Atlantic on the night of the sinking.
I am always amused at Hollywood's seemingly absolute desire to go all OCD on points that few people care about, but simply ignore major gaffes when it comes to actual reality itself, especially physics of Stuff.
Take Breaking Bad as a case in point-- the chemistry and physics of that series was supposedly good... yet? Upon close inspection, it was so far off as to be no better than the 1960's TV show of Batman...
You just have to kind of ignore physics, when watching movies.
Just as you have to ignore religion too, and politics, and actual human relationships, and history, and ..... !
That's the beauty of Fiction, I suppose. It's pretty much all Fantasy, All the Time.