They are closed on Sundays. They can schedule on Saturdays if it's not full. Since I'm in SolCal to pickup on Saturday it needs to be scheduled 7 days in advance meaning you probably can't pick it up on the earliest Saturday. I was given a 2 week pickup at Costa Mesa on a Saturday or pick it up at any time on a weekday.
There was no problem picking it up on a Saturday in San Diego. I got the call on a Tuesday and was given multiple choices of times the very next Saturday. At the delivery center, my rep said they were delivering about 16 cars that day. It looked like 2 owners were scheduled every 30 minutes from when they opened. When I left by noon, there were only like 2-3 cars left that had no one sitting in them yet.
Maybe just Marina Del Ray and Costa Mesa was full on Saturdays. Both was May 5th for me if I wanted weekend so i'm taking a day off work to pick it up today.