KLO - the basic set includes four peices for making the bodice. There is a later version that has a longer front piece, and that one is in more demand.
The sleeve has an add on item, and has a seperate instruction booklet. So if you find one with all five, make sure it's got both manuals also. Though I've got both manuals and will make copies of them at some point.
You'll also want to make sure you get one that is not missing a lot of the nuts for tightening down the adjustments. I'm missing a few, and I think there are a few missing rivets on the Sleeve piece too. I'll have to compare it to one that has everything and see how that goes.
There may have been other "add on" pieces too - with all the bragging on how many sold in the sales info I got with mine, one would expect to see more of these around.