Actually, Jeff. There are only two parts that are different on the heels that make them left or right and unfortunately the interior is where they are You can make a left a right but you need a broken right one so that you can take out the innards. Otherwise the cable will be pulling the mechanism the wrong way. I can post some pics at some point if you or anyone else is interested. Maybe if I find some time I can write up a heel FAQ.
I save my broken heels just for this so that I can make lefts, rights and rights lefts. The thing I usually break is the little wing on the front of the heel. Usually, everything else is fine on the heels so I save them.
->Ben