Like the others, I cannot answer your question authoritatively, but I think I can circumstantially.
I am having a rifle built by a forum gunsmith. When I first contacted him, he said I had three options for an action: custom, a 700 I already owned, or he could buy a complete rifle, disassemble it, and use that action.
So... that leads me to believe that even he could not buy an action without the other parts attached to it. However, if you want LA, here's one a few threads from yours.
FS SS Rem 700 LA MAG ACTION