Looking at EWR-LAX RT in April, and I spotted the sUA 772 they will be flying on the route (5 PM out to LAX, and 7 AM flight back the next day). On the website, though, I can't seem to be able to select any GF seats - 'First' shows up as United Business (not BF) as a P fare.
Perhaps you have to search the specific fare bucket to get it to show up? That's the only way that I could find a GF seat to pull in as United First (which was coming in at $2,850 v. $600 for BF...no thanks!).