Steve, That is the time for day hike pickup. Overnight pickup deadline is 10 AM the day of the hike.
If you call the Wilderness Permit Office number the day before, they will arrange to hold your permit until you show up.
In fact, if you "check in" online (and I think you can do that two weeks in advance), they hold it all day anyway. (However, I would not rely on this.) And please -- if you cancel or some of your party cancels, be sure to let them know so the slots can be made available to others!! In fact, leading up to your hike, if anyone cancels, go online and release the slot(s).
In the past, they have even put permits into a night pickup box by the road in front of the Visitor Center for people who arrived after closing. There may be some restriction on this, though, like having used their system before, so you know the WAG Bag rules, etc. Call the permit office and ask: 760-873-2483
(By the way: Good luck on the day hike without any acclimatization.)
