You can find out if you are on one of the new aircraft by doing a dummy booking in C for the dates you are travelling. Then look at the seatmap. If 1 A+C are missing then it is one of the older aircraft (most likely DAA or EWR) as these aircraft have had 2 seats removed in order to make room for the pilots rest area.

If 1A+C are still there, then its one od the new aircraft.

However, i dont think the new aircraft are being used on LAX route much these days. Which doesnt make sense as i think the new C lie-flat seats are wasted on overnight flights coming home from BOS/JFK as these flights are usually only 6-7 hours, as opposed to LAX at 10 hours.