Here is the item I bought. I took the ground glass portion off to put on a new Bellows Extension back for my FA that came without the ground glass. I was left with two other frame pieces that are not compatible with the FA and that I suspect are LE parts. I'm guessing from the L-series manual they are #23705 "4x5 Main Frame" and #23707 "4x5 Connecting Frame" I'll bring them for you.
My new extension back...say "hello" to long lenses!