This is from a great article published at the time--I have a magazine copy.
As you can see in the first line, Fincher certainly was involved in the pre-production, though as we know sets were under construction.
http://www.movie-list.com/forum/showthread.php?t=7415
With Fincher signed, Fox hired Larry Ferguson to do a four-week emergency rewite on the script. The plot Fincher came up with on his own, prior to the hiring of Ferguson, left the suits aghast. “They said, ‘My God, this is four f***ing hours, it’s $150 million.’ And they were absolutely right.” He laughs. “I was just so taken with the legacy that it had to be….Apocalypse Now.”
Fincher: In the draft Larry was writing, she was going to be this women who had fallen from the stars. In the end she dies, and there are seven monks left – seven dwarfs.
Q: You’re kidding.
Fincher: Seriously. I swear to God. She was like….what’s her name in Peter Pan? She was like Wendy. And she would make up all these stories. And in the end, there were these seven dwarfs left, and there was this f***ing tube they put her in, and they were waiting for Prince Charming to come wake her up. So that was one of the endings we had for this movie. You can imagine what Joe Roth said when he heard this. “What?! What are they doing over there?! What the f**k is going on?!”
When Ferguson turned in his draft, the movie almost fell apart. Fox coughed up $600,000 or so for Hill & Giler to do an emergency rewrite. The producers scraped Wards wooden planet and moved the action back to Twohy’s prison setting. Since both Fincher and Weaver were taken with the religious element of Ward’s story, they made the prisoners what Giler terms as “your basic militant Christian fundamentalist millenarian apocalyptic” types. In just three weeks they had a first draft. The studio liked it, Weaver liked it. But alas, Fincher had a few reservations.
The start date was pushed back to January 14 1991, and for the next 2 months, Hill, Giler, Fincher and the studio fought over the script, budget, the sets – even as more sets were being constructed. Hill calls the period “brutal, a real battle royal.”
In a tense meeting between Fincher, Michael London, Tom Jacobson and line producer, Ezra Swerdlow, Fox cut the shooting schedule down from 93 days to just 70. Fincher would only get 25 SFX shots (less than half what Aliens had). The filmmakers ended up working eighteen-hour days and six-day weeks, just to try and met the stop date. At one point, when an explosion effect backfired, five crewmembers got burned, one badly enough to go to hospital.
Once more last minute fight cost Fincher the goodwill of his producer-writers. Over the Christmas holidays, Hill & Giler were going to take a ten-day vacation, and a writer named Rex Pickett was hired for one more bit of rewriting. Fincher took Pickett out to dinner and told him all the problems he was having with the script. “I said, ‘Am I crazy? Am I totally insane?’ ” Fincher recalls. “And he said ‘No, this makes sense. Maybe you’re just not communicating it well.’ ”
It all blew up when Pickett wrote a memo savaging Hill & Giler’s script. Giler read the memo and exploded. “I was p***ed, absolutely furious,” says Giler. Hill said the thrust of the memo was “that we were fools not to recognise the merit of the ideas the director had.” Although Pickett’s rewrite was thrown out (he wouldn’t comment), the irate producers left London and never came back.
