"Does that mean that the 2nd largest will also be left-threaded?'' yes it does,
2 LH thread into a shoulder on the body.
there are a couple different stages of RH thread for the smaller ones,
that thread into each other and the other side of the same flange.
so with a freewheel vise and a couple chain-whips, you should be able to unscrew the cogs from one body. and swap them over to the other body..
the trick is getting that last cog off..
maybe a good soaking in solvent an re lubricating the 'bad' one will do..