I only measured one…let me see if they are all the same…
The one in the middle on the bottom is shorter (the one the original board revision systems don't have). The rest are the same.
I was gonna measure mine the next time I have it open, but I don't know when that will be. That system is like my hot rod -- I've had it open a lot to do work on it, but now one of the screw holes has its threads stripped, so the screw doesn't tighten anymore. Anyone opening your AES, please turn your screws counter-clockwise before screwing them back in to try and line up the threads, and don't screw them in too tight. The old plastic can't take too much abuse.