I'm still going through what few photos I can find of Essex in that time frame, but so far, I think all of the flight deck galleries are correct, and I believe that the island galleries and mounts are correct; if they aren't correct mount for mount, then at least the gallery tubs and shielding is right and the number of mounts might need to be varied.
One thing to watch is the two 2 gun galleries hanging off of the after end of the flight deck. Sixth photo down on this page: http://www.navsource.org/archives/02/09.htm Those were removed fairly early on from Essex, and may or may not have been there on CV-10.
I hope to get some time to do further research this upcoming long weekend and fix it in my mind if the kit mounts and positions are good enough. I'm starting to believe they are, but I want to do a final once-over to convince myself.
I've used the L'Arsenal 20mm mounts on previous projects, such as my USS Laffey kitbash (photos here at ModelWarships.com http://www.modelwarships.com/reviews/ships/cl/cl-52/350-dp/diorama/diorama.htm ) I was thinking of getting some of them for the Essex, but that's a chunk of change, as you know; and the same reason I probably won't get their 40mm mounts, as beautiful as they are. I think the 20mm's mounts in the kit can be salvaged: cut off the oversized barrel and replace with wire, and use PE splinter shields, sights, etc.
I did pick up the L'Arsenal 5" turrets and the associated directors. The many sided plastic ones that Trumpeter provides just don't do it for me, so many gaps and so much sanding that all of the detail disappears. You can't go wrong with the L'Arsenal equipment.
-Devin