105 - Jockey Wheels

[HLaB]

I've just taken mine apart (105 Jockey Wheels) and serviced them I noticed that the top one has an internal washer and the bottom doesn't, is that right, Shimano Tech Docs don't appear to show it:
Top:

Bottom:

Also they are looking a little sharp is there much to be gained from replacing them?
CRC have a few Tacx SS, Tacx Ceramic and Ultegra.

 

[spacecat]

Yes that's right. The top one is a 'centeron' wheel which is designed to move laterally on its axis. It's supposed to adjust its position for slightly out of adjustment indexing and 'centeron' the sprocket...........I actually filed mine down a little to reduce the play, as I'm convinced it makes matters worse on a worn drivetrain